JP3710339B2 - GaN compound semiconductor light emitting device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a GaN-based compound semiconductor light emitting device having high emission intensity at a peak emission wavelength.
[0002]
[Prior art]
Conventionally, GaN-based compound semiconductors have been used and studied as materials for light-emitting elements and high-power devices. For example, in the case of a light-emitting element, it is technically possible to realize a light-emitting element that emits light of a wide wavelength range from blue to orange by appropriately adjusting the composition of the GaN-based compound semiconductor constituting the light-emitting element. is there. In recent years, blue light-emitting diodes and green light-emitting diodes have been put into practical use as light-emitting diodes utilizing such characteristics of GaN-based compound semiconductors, and blue-violet semiconductor lasers have been developed as semiconductor laser elements.
[0003]
When producing a light emitting device as described above using a GaN-based compound semiconductor, normally, a current injection layer exhibiting n-type characteristics, a light-emitting layer, and p-type characteristics on a substrate on which the GaN-based compound semiconductor is epitaxially grown. Are sequentially formed. A sapphire substrate or the like can be used as the substrate. It is known that when a quantum well having a thickness of 10 nm or less is used as the light emitting layer, the light emission intensity is increased. Furthermore, the emission wavelength can be changed by adjusting the composition ratio (InN composition ratio) of indium (In) and nitrogen (N) in the light emitting layer.
[0004]
In general, as a quantum well used for a light emitting layer, a structure composed of only one well layer is also known, but a method using a multiple quantum well structure (MQW) having a well layer and a barrier layer is known. However, it is known that the light emission efficiency is higher than that in the case of using the structure consisting of only one layer as described above.
[0005]
Throughout this specification, a well layer or a quantum well layer refers to a layer in a quantum well structure that is in contact with a barrier layer and has a band gap energy smaller than that of the barrier layer, whereas a barrier layer is a quantum well structure. The layer in contact with the well layer and having a larger band gap energy than the well layer. In addition, the light emitting layer refers to a layer (laminated structure) contributing to light emission having a quantum well structure composed of a well layer and a barrier layer.
[0006]
However, when a light-emitting device is manufactured using a quantum well structure made of a GaN-based compound semiconductor containing In, the chemical thermal equilibrium state during crystal growth of a GaN-based compound semiconductor containing In (for example, InGaN) is extremely high. The quantum well structure has a predetermined InN composition (InGaN is composed of x% InN and (100-x)% GaN, and indicates the ratio of InN). Is difficult to form. Even if a quantum well structure having a predetermined InN composition can be formed, it is difficult to form a quantum well layer having high crystallinity, and thus a light emitting element having high light emission efficiency is realized. Is difficult.
[0007]
Furthermore, the InN composition and film thickness of a GaN-based compound semiconductor film having In that forms a quantum well structure are usually not uniform over the entire surface of the substrate. As described above, since the uniformity of the film thickness cannot be obtained over the entire surface of the substrate, it is difficult to manufacture a light-emitting element having the light emission intensity at the target light emission wavelength or peak light emission wavelength uniformly over the entire surface of the substrate. is there.
[0008]
In order to solve the above problem, an attempt is made to interrupt the growth after the light emitting layer is grown.
[0009]
Throughout this specification, the term “growth interruption” refers to a temperature range close to the growth temperature of a light emitting layer made of a GaN compound semiconductor (for example, when the light emitting layer is made of a GaN compound semiconductor containing indium). In the temperature range of preferably 650 ° C. or higher and 850 ° C. or lower), the supply of at least the group III raw material is to be stopped.
[0010]
For example, Japanese Patent Application Laid-Open No. 9-36429 describes that in the manufacture of a light emitting device, after a single quantum well light emitting layer made of InGaAlN is grown, the growth is interrupted for 2 minutes to 5 minutes. It is described that a light-emitting element having a uniform light emission state and a high yield can be obtained.
[0011]
As another prior art example, Japanese Patent Application Laid-Open No. 10-126006 discloses a light emitting device having a multiple quantum well (MQW) having three well layers as a light emitting layer. It has been shown that a quantum well semiconductor laser having a lower oscillation threshold current density and a higher characteristic temperature can be realized by performing subsequent semiconductor layer formation after a lapse of 5 seconds after formation. .
[0012]
[Problems to be solved by the invention]
However, even if an attempt is made to produce a light emitting diode having a higher light emission efficiency or a semiconductor laser having a lower threshold due to the interruption of growth in the prior art as described above, it has excellent monochromaticity and has a predetermined light emission efficiency at a target wavelength. It is not possible to obtain a light emitting element having Therefore, it is required to manufacture a light emitting element including a light emitting layer having higher light emission efficiency at a peak emission wavelength.
[0013]
The present invention has been made to solve the above-mentioned problems, and its object is to provide a method for producing a GaN-based compound semiconductor light-emitting element having a light-emitting layer with higher light emission efficiency at a peak light emission wavelength. It is.
[0014]
[Means for Solving the Problems]
ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a GaN-type compound semiconductor light-emitting device provided with the light emitting layer which has a quantum well structure is provided. The quantum well structure includes n + 1 barrier layers (where n is a natural number of 1 or more) each made of a GaN-based compound semiconductor containing indium, and GaN-based compound semiconductors each containing indium. An n-th well layer having a small band gap energy, and the m-th (1 ≦ m ≦ n) well layer is between the m-th barrier layer and the m + 1-th barrier layer. Adjacent to each other. The manufacturing method includes a step of crystal-growing the m-th barrier layer, a step of crystal-growing the m-th well layer on the m-th barrier layer, and on the m-th well layer. The step of crystal-growing the m + 1-th barrier layer is sequentially repeated in the reactor, and the light-emitting layer is formed by alternately growing the n + 1 barrier layers and the n-well layers. In the light emitting layer forming step, in each of the crystal growth steps of the well layer, after the completion of the crystal growth, a growth interruption for a first predetermined time is performed, thereby The aforementioned objective is achieved.
[0015]
However, the outermost barrier layer (the first barrier layer and / or the (n + 1) th barrier layer) in the quantum well structure of the light emitting layer may be omitted. In this case, the layer located outside the light emitting layer also serves as the omitted barrier layer.
[0016]
Preferably, the first predetermined time of the growth interruption in the crystal growth step of the well layer is set in a range of 10 seconds to 100 seconds.
[0017]
In the light emitting layer forming step, in each of the barrier layer crystal growth steps, the growth may be interrupted for a second predetermined time after the completion of the crystal growth.
[0018]
Preferably, the second predetermined time of the growth interruption in the crystal growth step of the barrier layer is set in a range of 1 second to 60 minutes.
[0019]
When the growth is interrupted, a carrier gas mainly containing nitrogen gas may be flowed into the reactor.
[0020]
Alternatively, when the growth is interrupted, a carrier gas mainly containing nitrogen gas and a group V source gas may be flowed into the reactor.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, in manufacturing a light emitting device including a light emitting layer composed of a plurality of GaN compound semiconductor layers each containing In, the light emitting layer is divided into a plurality of well layers (that is, two or more well layers). When forming from the barrier layer, the growth is interrupted for a certain time after the formation of each well layer and each barrier layer. In particular, by setting the length of the growth interruption period (growth interruption time) within a predetermined range, quantum well-ordered InGaN dots that contribute to light emission are formed with good uniformity in the well layer, While promoting the quantum effect by dot formation, the dispersion | variation in the light emission wavelength between each dot can be suppressed. As a result, the FWHM of the emission wavelength of the finally formed GaN-based compound semiconductor light-emitting element is reduced, and a remarkable increase in light emission efficiency is realized.
[0022]
When the growth interruption time is too short, the formation of InGaN dots becomes insufficient and non-uniform, while when the growth interruption time is too long, separation of In and the like from the surface vicinity of the growth surface occurs. As the surface of the growth surface becomes rough, decomposition of the InGaN dots occurs. In either case, the light emission efficiency at the peak light emission wavelength from the light emitting layer decreases. The InGaN dots described in the specification of the present application refer to a massive region having a grain size of about 1 nm to 5 nm, in which the In composition is relatively higher than the surrounding region in the well layer of the light emitting layer. And is also referred to as an (InGaN) quantum box.
[0023]
In the structure of the light emitting layer having InGaN quantum dots as described above, the Fermi level can be increased efficiently with fewer carrier injections than in a simple quantum well structure. Therefore, if InGaN dots can be formed with good uniformity in the well layer constituting the light emitting layer, the light emission efficiency at the peak light emission wavelength can be greatly improved.
[0024]
A preferable range of the length of the growth interruption period (growth interruption time) is 1 second or more and 60 minutes or less with respect to the growth interruption after the growth of the barrier layer made of the GaN-based compound semiconductor. For the growth interruption after the growth of the well layer composed of 10 seconds or more and 100 seconds or less, by setting the growth interruption time within these ranges, the effect as described above is particularly exhibited. Is done.
[0025]
Further, a more remarkable effect can be obtained by supplying a carrier gas mainly containing nitrogen during the growth interruption period. Furthermore, if a V group source gas is further mixed and flowed into the carrier gas, a more preferable effect can be obtained.
[0026]
Hereinafter, some specific embodiments of a method for manufacturing a GaN-based compound semiconductor light emitting device according to the present invention having the above-described features will be described with reference to the accompanying drawings.
[0027]
(First embodiment)
In the present embodiment, the present invention will be described by taking a GaN-based compound semiconductor light emitting device (specifically, a light emitting diode) manufactured by using MOCVD as a growth method using sapphire as a substrate. However, usable substrate materials and crystal growth methods are not limited to these.
[0028]
First, an outline of a known MOCVD apparatus used as a growth apparatus in the manufacturing method of the present invention will be described with reference to FIG.
[0029]
In the apparatus configuration of FIG. 2, a substrate 201 (sapphire substrate) having a (0001) plane for crystal growth of a GaN-based compound semiconductor layer is disposed on a susceptor 202 made of carbon. Inside the susceptor 202, a resistance heater (not shown) made of carbon is also disposed. By controlling the current flowing through the heater using a thermocouple, the temperature of the substrate 201 can be controlled. These substrate 201 and susceptor 202 are accommodated in a double reactor 203 made of quartz. The reactor 203 is water cooled.
[0030]
The group V material and group III material of the GaN compound semiconductor crystal grown on the substrate 201 are carrier gas (H ₂ Or N ₂ ) And mixed gas 210 is introduced into the reactor 203 from the raw material inlet 204 and discharged from the exhaust gas outlet 205. Group V materials include ammonia (NH _Three 206 and trimethylgallium (TMG) 207a, trimethylaluminum (TMA) 207b, and trimethylindium (TMI) 207c were bubbled with nitrogen gas or hydrogen gas. As an n-type doping material, SiH _Four 209, and p-type doping material is biscyclopentadienylmagnesium (Cp ₂ Mg) 207d was used. The flow rate of each raw material is accurately controlled by the mass flow controller MFC.
[0031]
Next, a crystal growth procedure for forming a GaN-based compound semiconductor light-emitting diode using the above-described MOCVD apparatus will be described below with reference to FIGS. FIG. 1 is a timing chart showing the crystal growth temperature and the supply amount of each source gas in the growth of the semiconductor layer near the light emitting layer. FIG. 3 is a schematic cross-sectional view schematically showing the configuration of the GaN-based compound semiconductor light-emitting diode 300 to be formed.
[0032]
First, the sapphire substrate 301 having the (0001) plane is cleaned and placed inside the MOCVD apparatus (at the position of reference numeral 201 in FIG. 2). The substrate 301 is then heat treated in a hydrogen atmosphere (ie, flowing hydrogen as a carrier gas) at a temperature of about 1100 ° C. for about 10 minutes, after which the temperature is from about 500 ° C. to 600 ° C., for example, to about 550 ° C. Lower the temperature. When the temperature becomes constant, the carrier gas is changed from hydrogen to nitrogen, and nitrogen gas (N ₂ ) At a total flow rate of 10 liter / min, and ammonia (NH _Three ) At a rate of about 3 liters / min, and after a few seconds, in addition to this, TMG as a Group III material is supplied at a rate of about 20 μmol / min for about 1 minute. As a result, the GaN low temperature buffer layer 302 is grown to a thickness of about 30 nm. Here, delaying the start of the supply of TMG as a Group III material by several seconds from the start of the supply of ammonia as a Group V material causes the Group III material to control growth to flow in a state where the ammonia atmosphere is not stable. This is to prevent this.
[0033]
Thereafter, the supply of TMG is stopped and the temperature is raised to about 1050 ° C. Thereafter, TMG is again supplied at about 50 μmol / min, and SiH is used as an n-type doping material. _Four Gas is supplied at about 10 nmol / min to grow the n-type GaN layer 303 with a thickness of about 4 μm (the n-type GaN layer growth period 104 in FIG. 1).
[0034]
Thereafter, as shown in the cooling period 107 (FIG. 1), SiH _Four And TMG supply are stopped, and carrier gas (N ₂ ) And NH _Three In order to obtain a light emitting layer growth temperature for crystal growth of the light emitting layer 306 of the light emitting element, the substrate temperature is lowered from about 1050 ° C. to a range of about 700 ° C. to about 850 ° C. The light emitting layer growth temperature is one parameter that determines the light emission wavelength of the light emitting element, and the light emission wavelength tends to be longer as the temperature is lower. The substrate temperature in the range of about 700 ° C. to about 850 ° C. is a temperature for manufacturing a light emitting element that emits light having a wavelength of purple to green. If light having a wavelength other than the purple to green wavelength band is desired, another appropriate substrate temperature may be selected. For example, when the light emitting layer is formed of a GaN-based compound semiconductor material containing indium (In), the growth temperature of the light emitting layer is in the temperature range of 650 ° C. to 850 ° C., and the substrate temperature is selected within this range. It ’s fine.
[0035]
In the present embodiment, the substrate temperature is lowered to about 730 ° C. during the temperature lowering period 107.
[0036]
When the substrate temperature is stabilized, as shown in the barrier layer growth period 102a (FIG. 1), TMG is supplied at 10 μmol / min and TMI is supplied at 10 μmol / min, and the light emitting layer 306 is formed. _0.05 Ga _0.95 An N barrier layer (not shown) is grown to a thickness of about 5 nm. During the growth of the barrier layer, SiH _Four About 5 nmol / min. The barrier layer is a layer having a band cap energy larger than that of a well layer to be formed next.
[0037]
After the growth of the barrier layer, as shown in the well layer growth period 103a (FIG. 1), the supply amount of TMI is increased to 50 μmol / min, and the In constituting the light emitting layer 306 is formed. _0.2 Ga _0.8 An N well layer (not shown) is grown to a thickness of about 3 nm. Similar to the growth of the barrier layer, SiH _Four About 5 nmol / min. Here, the substrate temperature was maintained at the growth temperature of the light emitting layer.
[0038]
After the growth of the well layer, as shown in the growth interruption period 101a (FIG. 1), TMG and TMI (and SiH _Four ) Will be stopped and growth will be suspended. At this time, the carrier gas (N ₂ ) And NH _Three Gas is continuously supplied to maintain the substrate temperature at the growth temperature of the light emitting layer. In the present invention, the growth interruption period 101a performed after the formation of the barrier layer is preferably in the range of about 1 second to about 100 seconds.
[0039]
Thereafter, as shown in the second barrier layer growth period 102b (FIG. 1), TMG is 10 μmol / min and TMI is 10 μmol / min (and SiH _Four At 5 nmol / min) to grow the second barrier layer to a thickness of about 5 nm. Further, as shown in the second well layer growth period 103b (FIG. 1), the TMI supply amount is again increased to 50 μmol / min to grow the second well layer to a thickness of about 3 nm. After the growth of the second well layer, the growth interruption period 101b is provided again.
[0040]
In this way, the barrier layer growth step, the well layer growth step, and the growth interruption step are repeated in order to form a multiple quantum well structure including a predetermined number of well layers, and finally on the well layer. Growing the barrier layer. As a result, a light emitting layer 306 having a stacked structure composed of a well layer and a barrier layer and terminated with the barrier layer is formed. In this embodiment, referring to FIG. 1, a barrier layer growth period 102a, a well layer growth period 103a, a growth interruption period 101a, a barrier layer growth period 102b, a well layer growth period 103b, a growth interruption period 101b, and a barrier layer growth period 102c The above-described steps are repeated in the well layer growth period 103c, the growth interruption period 101c, and the barrier layer growth period 102d, and the light emitting layer has a stacked structure including three well layers and four barrier layers and terminated by the barrier layers. 306 is formed. However, the number of well layers is not limited to the above three layers.
[0041]
After the last barrier layer growth period 102d, a growth interruption period may or may not be provided. However, in the case where the number of well layers constituting the light emitting layer is two or less, the light emission intensity at the time of current injection of the formed light emitting element is more preferably provided after the last barrier layer growth period 102d. Becomes higher.
[0042]
After the growth of the InGaN light-emitting layer 306, as shown in the sublimation prevention layer growth period 106 (FIG. 1), TMG is 10 μmol / min, TMA is 5 μmol / min, and Cp is used as a p-type doping material. ₂ Mg is supplied to grow the p-type AlGaN layer 307 with a thickness of about 30 nm. The p-type AlGaN layer 307 is provided for the purpose of preventing sublimation of the InGaN light emitting layer 306.
[0043]
Thereafter, during the temperature rising period 108 (FIG. 1), TMG, TMA, and Cp ₂ The supply of Mg is stopped, and the substrate temperature is raised to about 1050 ° C. again. After raising the temperature of the substrate, as shown in the p-type GaN layer growth period 105 (FIG. 1), TMG is 50 μmol / min, and Cp ₂ Mg is supplied, and the p-type GaN contact layer 310 is grown to a thickness of about 0.5 μm. After the growth, TMG and Cp ₂ The supply of Mg is stopped and the substrate heating is finished.
[0044]
When the substrate temperature is approximately room temperature, the substrate fabricated as described above is taken out from the crystal growth apparatus and etched from the upper surface to the middle of the n-type GaN layer 303 with respect to the crystal growth direction using reactive ion etching. Then, an exposed surface of the n-type GaN layer 303 is formed. Thereafter, an insulating layer 311 having a predetermined shape is formed, and a p-type electrode 312a and an n-type electrode 312b are further formed by vapor deposition.
[0045]
Thereby, the GaN-based compound semiconductor light-emitting diode 300 having the configuration as shown in FIG. 3 is completed.
[0046]
In the above, the exposed surface of the n-type GaN layer 303 is formed by reactive ion etching because an insulating sapphire substrate is used as the substrate 301. When using a substrate made of a conductive material such as GaN or SiC instead of the sapphire substrate, the exposed surface of the n-type GaN layer 303 is formed as described above, and the n-type is formed thereon. It is not necessary to form the electrode 312b, and the n-type electrode 312b may be formed directly on the back surface of the substrate 301.
[0047]
Furthermore, in the above description, the growth is interrupted only after the growth of the well layer is completed, but a growth interruption period (not shown) is also provided after the growth of the barrier layer, and similarly, TMG and TMI (and SiH) are provided. _Four ) Is stopped and the growth is interrupted, the light emission efficiency of the formed light emitting element is further improved.
[0048]
In the manufacturing process as described above, when the light emitting layer 306 is formed, the growth temperature is set to 780 ° C., the growth interruption time after the well layer growth is set to 5 seconds, 15 seconds, and 2 minutes, respectively. (The number of well layers in each sample is three), and the in-plane distribution of the emission wavelength from the light emitting layer was measured using a microscopic PL having a diameter of 1 μm. In FIGS. 4 to 6, as a result of the above measurement, for each of the cases where the growth interruption time after the well layer growth is 5 seconds, 15 seconds, and 2 minutes, The number distribution (frequency distribution) is shown. In the following description, as shown in FIGS. 4 to 6, the distribution (frequency distribution) of the relationship between the number of light emitting sites emitting light at each emission wavelength and the emission wavelength is graphed. The obtained curve is also referred to as “emission wavelength distribution curve”. Moreover, let the half value width of this emission wavelength part distribution curve be the half value width of the emission wavelength.
[0049]
In creating the emission wavelength distribution curves of FIGS. 4 to 6, the emission wavelength is converted in increments of 0.125 nm. When the numerical value after the decimal point of the wavelength is 0.00 or more and less than 0.125 nm, 0.0625 nm, In the case of 0.125 nm or more and less than 0.250 nm, 0.1875 nm, in the case of 0.250 nm or more and less than 0.375 nm, 0.3125 nm, in the case of 0.375 nm or more and less than 0.500 nm, 0.4375 nm,. 0.5625 nm for 500 nm or more and less than 0.625 nm, 0.6875 nm for 0.625 nm or more and less than 0.750 nm, 0.8125 nm or 0.875 nm or more for 0.750 nm or more and less than 0.875 nm In the case of less than 1.000 nm, it was converted to 0.9375 nm.
[0050]
From the results of FIGS. 4 to 6, when the growth interruption time is set to 15 seconds as compared with the case where the growth interruption time is set to 5 seconds (FIG. 4) and 2 minutes (FIG. 6) (FIG. 5). In addition, the half-value width of the emission wavelength is the narrowest, and the monochromaticity is increased.
[0051]
Next, in the manufacturing process described above, the growth temperature during the formation of the light emitting layer 306 is set to 730 ° C., 750 ° C., and 770 ° C., and the growth interruption time after the well layer growth is set to various values. Samples of the light-emitting diode were prepared (the number of well layers in each sample was three), and the in-plane distribution of the emission wavelength from the light-emitting layer was measured using a micro-PL having a diameter of 1 μm as described above. FIG. 7 shows the relationship between the reciprocal of the half-value width of the emission wavelength distribution curve and the growth interruption time after growth of the well layer as a result of the above measurement. Here, “the reciprocal of the half-value width of the emission wavelength distribution curve” is a value indicating the degree of variation in the distribution of the emission wavelength measured by the micro PL from the InGaN quantum dots, and if this value increases, the half-value width This means that the variation in the distribution of the emission wavelength measured with the micro PL from the InGaN quantum dots is reduced.
[0052]
In FIG. 7, the reciprocal of the half-value width in the emission wavelength distribution curve obtained when the growth temperature of the light emitting layer is set to 770 ° C. and the growth interruption time after the well layer growth is set to 20 seconds is 1 It has become.
[0053]
Further, in the manufacturing process described above, the growth temperature during the formation of the light emitting layer 306 was set to 730 ° C., 750 ° C., and 770 ° C., and the growth interruption time after the well layer growth was set to various values, respectively. For light-emitting diode samples (each sample has three well layers), the emission intensity at the peak emission wavelength obtained when a current of 20 mA was injected and the growth interruption time after growth of the well layer The relationship is shown in FIG. Note that the broken line at the emission intensity level 10 in FIG. 8 indicates the peak light emission obtained when no growth interruption is performed at the time of formation of the light emitting layer at each growth temperature (when the growth interruption time = 0 seconds). The emission intensity level at the wavelength is shown.
[0054]
Further, in FIG. 9, in the manufacturing process described above, the growth temperature when forming the light emitting layer 306 is set to 770 ° C., 790 ° C., and 810 ° C., and the growth interruption time after the well layer growth is set to various values. Then, for each of the light-emitting diode samples produced (the number of well layers in each sample is three), the inverse of the half-value width of the emission wavelength distribution curve measured and produced in the same manner as in FIG. It shows the relationship with the growth interruption time. In FIG. 9, the reciprocal of the half width in the emission wavelength distribution curve obtained when the growth temperature of the light emitting layer is set to 770 ° C. and the growth interruption time after the well layer growth is set to 20 seconds is 1 It has become.
[0055]
Further, in FIG. 10, in the manufacturing process described above, the growth temperature when forming the light emitting layer 306 is set to 770 ° C., 790 ° C., and 810 ° C., and the growth interruption time after the well layer growth is set to various values. Then, for each of the light-emitting diode samples fabricated (the number of well layers in each sample is three), the emission intensity at the peak emission wavelength obtained at the time of current injection of 20 mA as in FIG. It shows the relationship with the growth interruption time. Also in FIG. 10, the broken line at the emission intensity level 10 in the figure is obtained when growth is not interrupted at the time of formation of the light emitting layer at each growth temperature (when the growth interrupt time is 0 second). The emission intensity level at the peak emission wavelength is shown.
[0056]
7 and 9, when the growth interruption time is in the range of about 10 seconds to about 100 seconds for each growth temperature, the reciprocal value of the half width of the emission wavelength distribution curve is large. This means that the half-value width is reduced, that is, the variation in the distribution of the emission wavelength measured by the micro PL from the InGaN quantum dots is reduced, and the monochromaticity is being promoted as a whole of the light emitting surface. Is shown. On the other hand, from FIG. 8 and FIG. 10, when the growth interruption time is in the range of about 10 seconds to about 100 seconds, that is, in the range where the above-described monochromization (uniformization of InGaN quantum dots) occurs, It can be seen that the emission intensity at the wavelength increases.
[0057]
As described above, the mechanism by which the light emission characteristics of the formed GaN-based compound semiconductor light-emitting device are improved by the manufacturing process of the present invention in which the growth is interrupted for an appropriate time length when forming the light-emitting layer is understood as follows. Is done.
[0058]
A GaN-based compound semiconductor containing indium (In) grows in a chemically unstable state at high temperatures. Therefore, in the GaN-based compound semiconductor layer containing In, the crystal is in an unstable state immediately after the growth, and the crystallinity is not good. However, a well layer formed of such a GaN-based compound semiconductor containing In is subjected to N for a predetermined time in each growth temperature range after the growth. ₂ By exposing to heat in a gas atmosphere, InGaN dots of quantum size order that promote quantum effects are uniformly formed in the growth plane in the well layer, and variation in emission wavelength among the dots is suppressed. . As a result, the half-value width of the emission wavelength obtained in the manufactured light-emitting element is reduced (that is, monochromaticity is realized), the optical gain at the emission wavelength is increased, and the emission efficiency is significantly increased. On the other hand, when the growth interruption time is too short, the formation of InGaN dots becomes insufficient and non-uniform. On the other hand, when the growth interruption time is too long, In or the like from the vicinity of the surface of the growth surface. Occurs, the surface of the growth surface becomes rough, and decomposition of the InGaN dots occurs. In either case, the light emission efficiency at the peak light emission wavelength from the light emitting layer decreases.
[0059]
From the results shown in FIGS. 7 to 10, when the influence of the growth interruption time on the half-value width of the emission wavelength distribution curve indicating the degree of uniformity of the InGaN dots is examined again, the conventional technique shows a slight variation depending on the growth temperature. The half-width of the emission wavelength distribution curve at a growth interruption time of 10 seconds or more and 100 seconds or less, compared with the case where a light emitting layer was fabricated through a growth interruption of 5 seconds for a multiple quantum well structure as in Is narrower, and it can be seen that the uniformity of InGaN dots is further improved.
[0060]
Further, when the growth temperature of the light emitting layer is high, the growth interruption time is set short. On the other hand, when the growth temperature of the light emitting layer is low, the growth interruption time is set long. More specifically, when the growth temperature is in the range of 730 ° C. to 750 ° C., an effect can be obtained by setting the growth interruption time to 10 seconds or more and 100 seconds or less. By setting the second time to 90 seconds or less, a more remarkable effect can be obtained. When the growth temperature is in the range of 750 ° C. to 770 ° C., the effect can be obtained by setting the growth interruption time to 10 seconds or more and 100 seconds or less. In particular, the growth interruption time is set to 10 seconds or more and 80 seconds or less. By doing so, a more remarkable effect can be obtained. When the growth temperature is in the range of 770 ° C. to 790 ° C., the effect can be obtained by setting the growth interruption time to 10 seconds or more and 100 seconds or less. In particular, the growth interruption time is set to 10 seconds or more and 60 seconds or less. By doing so, a more remarkable effect can be obtained. Further, when the growth temperature is in the range of 790 ° C. to 810 ° C., an effect can be obtained by setting the growth interruption time to 10 seconds or more and 100 seconds or less, and in particular, the growth interruption time is 10 seconds or more and 50 seconds or less. By setting to, a more remarkable effect can be obtained.
[0061]
In the above description of the present embodiment, the case where the number of well layers included in the light emitting layer is three is described, but the number of well layers is not limited thereto. In particular, for multi-quantum wells in which the number of well layers is in the range of 2 to 20 layers, characteristics similar to those described above are obtained, and the growth of the light emitting layer with respect to the light emission intensity at the peak light emission wavelength is obtained. The influence of the temperature and the growth interruption time in the light emitting layer forming process showed almost the same tendency.
[0062]
In the quantum well structure of the light emitting layer, the same effect as described above can be obtained when there is no barrier layer below (outside) the first well layer or when there is no barrier layer above (outside) the last well layer. can get. Further, the growth conditions of the respective well layers may not be the same, and the growth conditions of the respective barrier layers may not be the same.
[0063]
In the configuration of FIG. 3 described above, a GaN film is used as the low-temperature buffer layer, but instead of this, Al _x Ga _1-x An N (0 ≦ x ≦ 1) layer or a ZnO layer may be used. In these cases, the same effect as described above is obtained.
[0064]
In this embodiment, a sapphire substrate having a (0001) plane is used as the substrate. However, the plane orientation does not have a particularly large effect on the effect of improving the emission intensity, and instead of the sapphire substrate. It has been confirmed that the same effect can be obtained even when other substrates made of GaN, SiC, spinel, mica, or the like are used. Further, when a GaN substrate is used as the substrate, it is not necessary to provide a pretreatment by heat treatment in a hydrogen atmosphere and a low-temperature buffer layer for epitaxial growth of the GaN layer. That is, when a GaN substrate is used, a carrier gas mainly composed of an inert gas and NH _Three Raise temperature in atmosphere, then TMG and / or SiH _Four And a light emitting device can be manufactured starting from the growth of the lower n-type GaN layer. Also in this case, the same effect as described above can be obtained.
[0065]
(Second Embodiment)
In the present embodiment, the present invention will be described by taking a GaN-based compound semiconductor light emitting element (specifically, a semiconductor laser) manufactured by using MOCVD as a growth method using sapphire as a substrate. In the following description, the growth temperature of the light emitting layer is set to 730 ° C., and the growth interruption for 15 seconds is carried out after the growth of the well layer constituting the light emitting layer. Possible substrate materials and crystal growth methods are not limited to those mentioned below.
[0066]
Also in this embodiment, the MOCVD apparatus described with reference to FIG. 2 in the first embodiment is used as a growth apparatus. A description of this MOCVD apparatus is omitted here.
[0067]
With respect to the crystal growth procedure for forming a GaN-based compound semiconductor laser using the MOCVD apparatus having the configuration of FIG. 2 in this embodiment, reference is again made to FIG. 1 referred to in the first embodiment, and FIG. This will be described below with reference. FIG. 11 is a schematic cross-sectional view schematically showing the configuration of the GaN-based compound semiconductor laser 350 formed in this embodiment.
[0068]
First, the sapphire substrate 301 having the (0001) plane is cleaned and placed inside the MOCVD apparatus (at the position of reference numeral 201 in FIG. 2). Next, the substrate 301 is heat-treated at a temperature of about 1100 ° C. for about 10 minutes in a hydrogen atmosphere (that is, flowing hydrogen as a carrier gas), and then the temperature is lowered to about 500 ° C. to 600 ° C., for example, about 550 ° C. To do. When the temperature becomes constant, the carrier gas is changed from hydrogen to nitrogen, and nitrogen gas (N ₂ ) At a total flow rate of 10 liter / min, and ammonia (NH _Three ) At a rate of about 3 liters / min, and after a few seconds, in addition to this, TMG as a Group III material is supplied at a rate of about 20 μmol / min for about 1 minute. As a result, the GaN low temperature buffer layer 302 is grown to a thickness of about 30 nm. Here, delaying the start of the supply of TMG as a Group III material by several seconds from the start of the supply of ammonia as a Group V material causes the Group III material to control growth to flow in a state where the ammonia atmosphere is not stable. This is to prevent this.
[0069]
Thereafter, the supply of TMG is stopped and the temperature is raised to about 1050 ° C. Thereafter, TMG is again supplied at about 50 μmol / min, and SiH is used as an n-type doping material. _Four A gas is supplied at about 10 nmol / min to grow the n-type GaN layer 303 with a thickness of about 4 μm.
[0070]
Next, carrier gas, ammonia, TMG, and SiH _Four In addition to gas supply, TMA is supplied at 10 μmol / min, and n-type Al _0.15 Ga _0.85 N light confinement layer 304 is grown to a thickness of about 0.5 μm.
[0071]
Next, as shown in the n-type GaN layer growth period 104 in FIG. 1, the supply of TMA is stopped, and the n-type GaN light guide layer 305 is grown to a thickness of about 0.1 μm.
[0072]
Thereafter, as shown in the cooling period 107 (FIG. 1), SiH _Four And TMG supply are stopped, and carrier gas (N ₂ ) And NH _Three In order to obtain a light emitting layer growth temperature for crystal growth of the light emitting layer 306 of the light emitting element, the substrate temperature is lowered to about 730 ° C. As described in the first embodiment, the light emitting layer growth temperature is one parameter for determining the light emission wavelength of the light emitting element, and shows a tendency that the light emission wavelength becomes longer as the temperature is lower. What is necessary is just to set suitably according to a wavelength.
[0073]
When the substrate temperature is stabilized, as shown in the barrier layer growth period 102a (FIG. 1), TMG is supplied at 10 μmol / min and TMI is supplied at 10 μmol / min, and the light emitting layer 306 is formed. _0.05 Ga _0.95 An N barrier layer (not shown) is grown to a thickness of about 5 nm. During the growth of the barrier layer, SiH _Four About 5 nmol / min. The barrier layer is a layer having a band cap energy larger than that of the well layer.
[0074]
After the growth of the barrier layer, as shown in the well layer growth period 103a (FIG. 1), the supply amount of TMI is increased to 50 μmol / min, and the In constituting the light emitting layer 306 is formed. _0.2 Ga _0.8 An N well layer (not shown) is grown to a thickness of about 3 nm. Similar to the growth of the barrier layer, SiH _Four About 5 nmol / min. Here, the substrate temperature was maintained at the growth temperature of the light emitting layer (730 ° C.).
[0075]
After the growth of the well layer, as shown in the growth interruption period 101a (FIG. 1), TMG and TMI (and SiH _Four ) Is stopped and the growth is interrupted for 20 seconds. At this time, the carrier gas (N ₂ ) And NH _Three The gas is continuously supplied to maintain the substrate temperature at the growth temperature of the barrier layer, that is, the growth temperature of the light emitting layer.
[0076]
Thereafter, as shown in the second barrier layer growth period 102b (FIG. 1), TMG is 10 μmol / min and TMI is 10 μmol / min (and SiH _Four At 5 nmol / min) to grow the second barrier layer to a thickness of about 5 nm. Further, as shown in the second well layer growth period 103b (FIG. 1), the TMI supply amount is again increased to 50 μmol / min to grow the second well layer to a thickness of about 3 nm. After the growth of the second well layer, the growth interruption period 101b is provided again.
[0077]
In this way, the barrier layer growth step, the well layer growth step, and the growth interruption step are repeated in order to form a multiple quantum well structure including a predetermined number of well layers, and finally on the well layer. Growing the barrier layer. As a result, a light emitting layer 306 having a stacked structure composed of a well layer and a barrier layer and terminated with the barrier layer is formed. In this embodiment, referring to FIG. 1, a barrier layer growth period 102a, a well layer growth period 103a, a growth interruption period 101a, a barrier layer growth period 102b, a well layer growth period 103b, a growth interruption period 101b, and a barrier layer growth period 102c The above-described steps are repeated in the well layer growth period 103c, the growth interruption period 101c, and the barrier layer growth period 102d, and the light emitting layer has a stacked structure including three well layers and four barrier layers and terminated by the barrier layers. 306 is formed. However, the number of well layers is not limited to three as described above, but may be other numbers.
[0078]
After the last barrier layer growth period 102d, a growth interruption period may or may not be provided. However, in the case where the number of well layers constituting the light emitting layer is two or less, the light emission intensity at the time of current injection of the formed light emitting element is more preferably provided after the last barrier layer growth period 102d. Becomes higher.
[0079]
After the growth of the InGaN light-emitting layer 306, as shown in the sublimation prevention layer growth period 106 (FIG. 1), TMG is 10 μmol / min, TMA is 5 μmol / min, and Cp is used as a p-type doping material. ₂ Mg is supplied to grow the p-type AlGaN layer 307 with a thickness of about 30 nm. The p-type AlGaN layer 307 is provided for the purpose of preventing sublimation of the InGaN light emitting layer 306.
[0080]
Thereafter, during the temperature rising period 108 (FIG. 1), TMG, TMA, and Cp ₂ The supply of Mg is stopped, and the substrate temperature is raised to about 1050 ° C. again. After raising the temperature of the substrate, as shown in the p-type GaN layer growth period 105 (FIG. 1), TMG is 50 μmol / min, and Cp ₂ Mg is supplied, and the p-type GaN light guide layer 308 is grown to a thickness of about 0.1 μm.
[0081]
Next, TMA was supplied at 10 μmol / min, and p-type Al _0.15 Ga _0.85 An N optical confinement layer 309 is grown to a thickness of about 0.5 μm. Thereafter, the supply of TMA is stopped, and the p-type GaN contact layer 310 is grown to a thickness of about 0.5 μm. After the growth, TMG and Cp ₂ The supply of Mg is stopped and the substrate heating is finished.
[0082]
When the substrate temperature reaches approximately room temperature, the substrate fabricated as described above is taken out of the crystal growth apparatus and placed in a heat treatment furnace. ₂ Heating is performed in an atmosphere at a temperature of 800 ° C. for 20 minutes to activate magnesium (Mg) in the growth film. Next, using photolithography and dry etching techniques, p is formed from the surface of the p-type GaN contact layer 310 in a predetermined region in parallel to the <1-100> direction of the GaN-based crystal of the grown p-type GaN contact layer 310. Type Al _0.15 Ga _0.85 The surface up to the surface of the N light confinement layer 309 is removed by etching to produce a mesa shape having a width of 30 μm and a length of 600 μm.
[0083]
Next, the insulating layer 311 having a predetermined shape (for example, SiO 2) is formed so as to cover the p-type GaN contact layer 310 patterned into a predetermined shape by etching as described above. ₂ Film). Subsequently, a region reaching the middle of the n-type GaN contact layer 303 from the upper surface in the crystal growth direction is removed by etching to form an exposed surface of the n-type GaN contact layer 303. Thereafter, an n-type electrode 312b made of Ti / Au is formed on the exposed surface of the n-type GaN contact layer 303 by, for example, vapor deposition, while a width of 2 μm and a length is formed on the p-type GaN contact layer 310. A p-type electrode 312a is formed to be joined at a thickness of 600 μm.
[0084]
Further, the grown GaN-based crystal is cleaved at the (1-100) plane to form an end face for extracting light, and a laser resonator having a length of 650 μm is formed. A silicon nitride film having a reflectance of 12% is formed on the front end face of the resonator, and a dielectric multilayer film having a reflectance of 70% made of a titanium oxide film and a magnesium fluoride film is formed on the back end face. Form each one. Finally, each chip is divided by scribing.
[0085]
Thereby, a GaN-based compound semiconductor laser 350 having a configuration as shown in FIG. 11 is completed.
[0086]
In the above, the exposed surface of the n-type GaN layer 303 is formed by etching because an insulating sapphire substrate is used as the substrate 301. When using a substrate made of a conductive material such as GaN or SiC instead of the sapphire substrate, the exposed surface of the n-type GaN layer 303 is formed as described above, and the n-type is formed thereon. It is not necessary to form the electrode 312b, and the n-type electrode 312b may be formed directly on the back surface of the substrate 301.
[0087]
Further, in the above description, the n-type layer, the light emitting layer, and the p-type layer are grown in this order from the side close to the substrate 301 to form a laminated structure, but conversely, from the side close to the substrate 301. A stacked structure may be formed by crystal growth in the order of a p-type layer, a light emitting layer, and an n-type layer.
[0088]
Furthermore, in the above description, the growth is interrupted only after the growth of the well layer is completed, but a growth interruption period (not shown) is also provided after the growth of the barrier layer, and similarly, TMG and TMI (and SiH) are provided. _Four ) Is stopped and the growth is interrupted, the light emission efficiency of the formed light emitting element is further improved. The growth interruption after the formation of the barrier layer is, for example, in the range of about 1 second to about 60 minutes. At this time, similarly to the interruption of growth after the formation of the well layer, the carrier gas and NH _Three The gas is continuously supplied to maintain the substrate temperature at the growth temperature of the barrier layer, that is, the growth temperature of the light emitting layer.
[0089]
The operating characteristics of the semiconductor laser according to the present embodiment manufactured as described above were measured. When operating at room temperature, the oscillation threshold current was 30 mA, the differential light emission efficiency was 0.98 W / A, and light was emitted at a low threshold. Highly efficient laser continuous oscillation was obtained. The operating current value at room temperature with an optical output of 35 mW was 61 mA, the operating voltage was 4.2 V, and the input power at this time was 256.2 mW. The value of this input power is a value required for the same room temperature operation with a light output of 35 mW in a semiconductor laser device fabricated by interrupting growth for 5 seconds when forming a light emitting layer having a multiple quantum well structure according to the prior art. (826.5 mW) of 31.0%, and a similar light output of 35 mW in a semiconductor laser device manufactured by interrupting growth for 2 minutes when forming a light emitting layer having a single quantum well structure according to the prior art Is 78.5% of the value (326.4 mW) required at room temperature operation. From this, it was confirmed that the operating performance of the device was greatly improved in the semiconductor laser device manufactured according to the present invention.
[0090]
For the purpose of confirming the improvement in the operating performance of the semiconductor laser device by the manufacturing method according to the present invention, a sample formed by the above-described process up to the evaporation prevention layer on the light emitting layer formation (this structure is easy for microscopic PL evaluation) The emission wavelength distribution curve in the growth plane was prepared by observation with a microscopic PL, and the half-value width of the obtained emission wavelength distribution curve was 33% of the value in the sample prepared by interrupting the growth for 5 seconds. It was 75% of the value in the sample prepared by interrupting the growth for 2 minutes, and the improvement of monochromaticity was confirmed. As in the case of the light-emitting diode described in the first embodiment, this is because the growth is interrupted after the growth of the well layer constituting the light-emitting layer, and N is applied for an optimum time corresponding to the predetermined growth temperature range. ₂ By exposing the well layer to heat in the atmosphere, quantum well-ordered InGaN dots that promote quantum effects are uniformly formed in the growth plane in the well layer, and variation in emission wavelength among the dots is suppressed. Because. As a result, the half-value width of the emission wavelength obtained with the manufactured light-emitting element is reduced, the optical gain at the emission wavelength is increased, and a semiconductor laser with a low threshold and high emission efficiency is realized.
[0091]
In the above description, the case where the number of well layers included in the light emitting layer is three is described. However, the number of well layers is not limited thereto. In particular, the same effect as described above can be obtained for a multiple quantum well in which the number of well layers is in the range of 2 to 20 layers.
[0092]
In the quantum well structure of the light emitting layer, the same effect as described above can be obtained when there is no barrier layer below (outside) the first well layer or when there is no barrier layer above (outside) the last well layer. can get. Further, the growth conditions of the respective well layers may not be the same, and the growth conditions of the respective barrier layers may not be the same.
[0093]
In the configuration shown in FIG. 11 described above, a GaN film is used as the low-temperature buffer layer. _x Ga _1-x An N (0 ≦ x ≦ 1) layer or a ZnO layer may be used. In these cases, the same effect as described above is obtained.
[0094]
In this embodiment, a sapphire substrate having a (0001) plane is used as the substrate. However, the plane orientation does not have a particularly large effect on the effect of improving the emission intensity, and instead of the sapphire substrate. It has been confirmed that the same effect can be obtained even when other substrates made of GaN, SiC, spinel, mica, or the like are used. Further, when a GaN substrate is used as the substrate, it is not necessary to provide a pretreatment by heat treatment in a hydrogen atmosphere and a low-temperature buffer layer for epitaxial growth of the GaN layer. That is, when a GaN substrate is used, a carrier gas mainly composed of an inert gas and NH _Three Raise temperature in atmosphere, then TMG and / or SiH _Four And a light emitting device can be manufactured starting from the growth of the lower n-type GaN layer. Also in this case, the same effect as described above can be obtained.
[0095]
Further, in the above description, the nitrogen compound semiconductor laser 350 in which both the n-type electrode 312b and the p-type electrode 312a are disposed on the upper surface of the light emitting element is described. However, a conductive material such as GaN or SiC is used instead of the sapphire substrate. A nitrogen compound semiconductor laser 360 having a configuration in which one electrode (for example, the n-type electrode 312b) is provided on the back surface of the substrate 301 as shown in FIG. In the case of using a substrate made of a material that can obtain an appropriate level of lattice matching with the growth layer, it is not necessary to provide a buffer layer. In the semiconductor laser 360 of FIG. 15, constituent members corresponding to those in the configuration of the semiconductor laser 350 shown in FIG. 11 are given the same reference numerals, and descriptions thereof are omitted here.
[0096]
In the case of manufacturing a semiconductor laser having another configuration as described above, the effects as described above can be obtained by applying the present invention.
[0097]
(Third embodiment)
In the present embodiment, a semiconductor laser was fabricated by forming a light emitting layer with a growth temperature of about 730 ° C. as in the second embodiment and a growth interruption time after formation of a well layer of 90 seconds.
[0098]
When the operating characteristics of the semiconductor laser in this embodiment were measured, when operating at room temperature, the oscillation threshold current was 34 mA, the differential emission efficiency was 0.96 W / A, and the laser continuity with a low threshold and high emission efficiency was obtained. Oscillation was obtained. In addition, when the emission wavelength distribution curve in the growth plane was created by observation with the microscopic PL, the half-value width of the obtained emission wavelength distribution curve was 5 seconds during the formation of the light emitting layer having the multiple quantum well structure according to the prior art. 29% of the value in the semiconductor laser device manufactured by interrupting, and 70% of the value in the semiconductor laser device manufactured by interrupting the growth for 2 minutes when forming the light emitting layer having a single quantum well structure according to the prior art. Improvement of monochromaticity was confirmed.
[0099]
Furthermore, in the semiconductor laser of this embodiment, the input power required for room temperature operation with an optical output of 35 mW was 248.0 mW. The value of this input power is a value required for the same room temperature operation with a light output of 35 mW in a semiconductor laser device fabricated by interrupting growth for 5 seconds when forming a light emitting layer having a multiple quantum well structure according to the prior art. (826.5 mW) of 30.0%, and a similar light output of 35 mW in a semiconductor laser device manufactured by interrupting growth for 2 minutes when forming a light emitting layer having a single quantum well structure according to the prior art Is 76.0% of the value (326.4 mW) required during room temperature operation.
[0100]
As described above, it was confirmed that in the semiconductor laser device manufactured according to the present invention, the operation performance of the device was greatly improved by improving the monochromaticity, that is, improving the uniformity of the InGaN quantum dots.
[0101]
In the same manner as described above, a semiconductor laser having a light emitting layer prepared by setting the growth temperature of the light emitting layer to about 730 ° C. and the growth interruption time after the well layer growth to 10 seconds to 100 seconds is also 5 seconds or 2 minutes. Compared to the sample prepared by interrupting the growth according to the prior art, the same improvement in operating characteristics as above was confirmed.
[0102]
(Fourth embodiment)
In the present embodiment, a semiconductor laser was fabricated by forming a light emitting layer with a growth temperature of about 750 ° C. different from those of the second and third embodiments and a growth interruption time after the well layer formation of 10 seconds.
[0103]
Such a semiconductor laser in this embodiment oscillated continuously at room temperature. In addition, when the emission wavelength distribution curve in the growth plane was created by observation with the microscopic PL, the half-value width of the obtained emission wavelength distribution curve was 5 seconds during the formation of the light emitting layer having the multiple quantum well structure according to the conventional technique. 61.5% of the value in the semiconductor laser device manufactured by interrupting, 85. of the value in the semiconductor laser device manufactured by interrupting the growth for 2 minutes when forming the light emitting layer having a single quantum well structure according to the prior art. It was 1%, and the improvement of monochromaticity was confirmed. In addition, the luminous efficiency has been improved with the improvement of the monochromaticity.
[0104]
On the other hand, when the growth temperature was about 750 ° C. as described above, the light emitting layer was formed with the growth interruption time after formation of the well layer being 90 seconds, and a semiconductor laser was produced, the obtained semiconductor laser was similarly at room temperature. Laser continuous oscillation. In addition, for this semiconductor laser, an emission wavelength distribution curve in the growth plane was created by observation with a microscopic PL. The half-value width of the obtained emission wavelength distribution curve was determined by the formation of a light emitting layer having a multiple quantum well structure in accordance with the prior art. More than the values in both the semiconductor laser device manufactured by occasionally interrupting the growth for 5 seconds and the semiconductor laser device manufactured by interrupting the growth for 2 minutes when forming the light emitting layer having a single quantum well structure according to the prior art It was confirmed that the device characteristics were improved. In addition, the luminous efficiency has been improved with the improvement of the monochromaticity.
[0105]
Similarly to the above description, a semiconductor laser having a light emitting layer formed with a growth temperature of the light emitting layer of about 750 ° C. and a growth interruption time after the well layer growth of 10 seconds to 100 seconds is also 5 seconds or 2 minutes. Compared to the sample prepared by interrupting the growth according to the prior art, the same improvement in operating characteristics as above was confirmed.
[0106]
Further, a light emitting layer produced by changing the growth temperature of the light emitting layer to about 770 ° C., about 790 ° C., or about 810 ° C. and changing the growth interruption time after the well layer growth in a range of 10 seconds to 100 seconds, respectively. Also in the semiconductor laser having the same, a significant improvement in the operating characteristics was confirmed in the same manner as described above as compared with the sample manufactured by performing the growth interruption according to the conventional technique of 5 seconds or 2 minutes.
[0107]
(Fifth embodiment)
In the present embodiment, during the growth of the light emitting layer composed of the barrier layer and the well layer, the growth is interrupted for a predetermined time after the formation of the barrier layer (first growth interruption), and the growth is also performed for a certain time after the well layer is formed. The interruption (second growth interruption) was performed to produce a GaN-based compound semiconductor light emitting device (specifically, a light emitting diode). Then, in the manufactured light emitting diode, an emission wavelength distribution curve in the growth plane is created by observation with a micro PL, and the half width of the obtained emission wavelength distribution curve and the length of the growth interruption period after the barrier layer formation (growth) (Interruption time).
[0108]
The manufacturing process of the light emitting diode is similar to the process performed in the first embodiment.
[0109]
Specifically, first, a GaN low-temperature buffer layer and an n-type GaN layer are sequentially formed on a sapphire substrate having a (0001) plane in the same manner as in the first embodiment.
[0110]
Next, a light emitting layer is formed on the n-type GaN layer. First, carrier gas and NH _Three The substrate temperature is adjusted to a predetermined temperature while flowing the gas. When the substrate temperature is stabilized, the carrier gas (N ₂ Ratio 100%, total flow rate 10 liters / min) and NH _Three In addition to gas (3 liters / min), TMG (10 μmol / min), TMI (10 μmol / min), and SiH _Four (5 nmol / min) _0.05 Ga _0.95 The N barrier layer was grown with an average thickness of about 5 nm. After formation of the barrier layer, TMG, TMI, and SiH _Four Supply is temporarily stopped, carrier gas and NH _Three The growth was interrupted for a predetermined time length (first growth interruption) in a state where the gas was continuously supplied and the predetermined substrate temperature was maintained. Then again TMG (10 μmol / min), TMI (50 μmol / min), and SiH _Four (5 nmol / min) _0.2 Ga _0.8 N well layers were grown with an average thickness of about 5 nm. After formation of the well layer, TMG, TMI, and SiH _Four Supply is temporarily stopped, carrier gas and NH _Three While the gas was continuously supplied and the predetermined substrate temperature was maintained, the growth interruption (second growth interruption) was performed for a predetermined period (for example, 20 seconds). Thereafter, the supply amount of TMI is reduced to 10 μmol / min, the supply amount of other raw materials is maintained, and In _0.05 Ga _0.95 The N barrier layer was grown with an average thickness of about 5 nm. Thereafter, in the same manner as described above, the first growth interruption step, the well layer growth step, the second growth interruption step, and the barrier layer growth step for a predetermined period are repeated, and finally the barrier layer is grown. A light emitting layer having a laminated structure terminated with a barrier layer was formed.
[0111]
Next, in the same manner as in the first embodiment, a p-type AlGaN sublimation preventing layer was grown on the light emitting layer to a thickness of about 30 nm. Here, whether or not to stop the growth between the growth step of the InGaN barrier layer that terminates the light emitting layer and the growth step of the p-type AlGaN sublimation prevention layer is arbitrary. However, when the number of well layers constituting the light emitting layer is two or less, it is preferable to provide a growth interruption period prior to the growth process of the p-type AlGaN sublimation prevention layer after the last barrier layer growth period 102d. The light emission intensity at the time of current injection of the formed light emitting element is increased.
[0112]
Next, in the same manner as in the first embodiment, a p-type GaN layer and an insulating layer having a predetermined shape were formed, and a p-type electrode and an n-type electrode were formed. As a result, a light emitting diode was produced.
[0113]
With respect to the light-emitting diode manufactured by the manufacturing process as described above, the in-plane distribution of the emission wavelength from the light-emitting layer was measured using a microscopic PL having a diameter of 1 μm. FIG. 12 shows the relationship between the reciprocal of the half-value width of the emission wavelength distribution curve and the growth interruption time after growth of the well layer as a result of the above measurement. In FIG. 12, the reciprocal of the half-value width in the emission wavelength distribution curve obtained when the growth interruption time after the well layer growth at each growth temperature is 0 seconds is 10 (position “10” on the vertical axis). (Corresponds to the dashed line drawn by
[0114]
From the results of FIG. 12, when the influence of the growth interruption time after the growth of the barrier layer on the half width of the emission wavelength distribution curve indicating the degree of uniformity of the InGaN dots is examined, the growth temperature is slightly changed depending on the growth temperature. In the case of 730 ° C., the growth interruption time is 1 second to about 60 minutes or less, in the case of the growth temperature 770 ° C., in the growth interruption time of 1 second to about 15 minutes, and in the case of the growth temperature 810 ° C., 1 second. In the growth interruption time of about 5 minutes or less, the half width of the emission wavelength distribution curve is narrower than that in the case where the growth interruption is not performed after the growth of the barrier layer, and the uniformity of the InGaN dots may progress. Understand. As the half-value width of the emission wavelength distribution curve is reduced (that is, the uniformity of the InGaN quantum dots is improved), the emission intensity at the peak emission wavelength is increased, and the operation performance of the light emitting device is greatly improved. confirmed.
[0115]
Further, when the growth temperature of the light emitting layer is high, the growth interruption time is set short. On the other hand, when the growth temperature of the light emitting layer is low, the growth interruption time is set long. More specifically, when the growth temperature is 730 ° C., an effect can be obtained by setting the growth interruption time to about 1 second to about 60 minutes. In particular, the growth interruption time is 1 second or more and 10 minutes or less. By setting to, a more remarkable effect can be obtained. When the growth temperature is 770 ° C., an effect can be obtained by setting the growth interruption time to 1 to 15 minutes, and in particular, by setting the growth interruption time to 1 second or more and 5 minutes or less, it becomes more prominent. An effect is obtained. Further, when the growth temperature is 810 ° C., the effect can be obtained by setting the growth interruption time to 1 second to 5 minutes. In particular, by setting the growth interruption time to 1 second or more and 2 minutes or less, A remarkable effect is obtained.
[0116]
The above results are considered to be achieved by the following mechanism. After the growth of the barrier layer formed from the GaN-based compound semiconductor, N is applied for a predetermined time in the growth temperature range. ₂ When exposed to heat in a gas atmosphere, the surface of the barrier layer is planarized. For this reason, the crystallinity of the well layer formed on the barrier layer is improved, and quantum size order InGaN dots that promote the quantum effect are uniformly formed in the well layer. Variations in the emission wavelength at are suppressed. As a result, the half-value width of the emission wavelength obtained in the manufactured light-emitting element is reduced (that is, monochromaticity is realized), the optical gain at the emission wavelength is increased, and the emission efficiency is significantly increased. If the growth interruption time is too long, separation of In or the like from the vicinity of the surface of the growth surface occurs, the surface of the growth surface becomes rough, and the crystallinity of the well layer formed thereon is rather disturbed, As a result, the light emission efficiency at the peak emission wavelength from the light emitting layer decreases.
[0117]
The above results are not limited to the case where the number of well layers constituting the light emitting layer is a specific value. In particular, the same effect as described above can be obtained for a multiple quantum well in which the number of well layers is in the range of 2 to 20 layers.
[0118]
In the quantum well structure of the light emitting layer, the same effect as described above can be obtained when there is no barrier layer below (outside) the first well layer or when there is no barrier layer above (outside) the last well layer. can get. Further, the growth conditions of the respective well layers may not be the same, and the growth conditions of the respective barrier layers may not be the same.
[0119]
If the growth is interrupted only after the growth of the barrier layer without interrupting the growth after the growth of the well layer, the emission intensity at the peak emission wavelength only increases up to about 2.5 times. The remarkable effect as shown in FIG. 12 was not confirmed.
[0120]
In the configuration of the present embodiment, a GaN film is used as the low-temperature buffer layer, but instead of this, Al _x Ga _1-x An N (0 ≦ x ≦ 1) layer or a ZnO layer may be used. In these cases, the same effect as described above is obtained.
[0121]
In this embodiment, a sapphire substrate having a (0001) plane is used as the substrate. However, the plane orientation does not have a particularly large effect on the effect of improving the emission intensity, and instead of the sapphire substrate. It has been confirmed that the same effect can be obtained even when other substrates made of GaN, SiC, spinel, mica, or the like are used. Further, when a GaN substrate is used as the substrate, it is not necessary to provide a pretreatment by heat treatment in a hydrogen atmosphere and a low-temperature buffer layer for epitaxial growth of the GaN layer. That is, when a GaN substrate is used, a carrier gas mainly composed of an inert gas and NH _Three Raise temperature in atmosphere, then TMG and / or SiH _Four And a light emitting device can be manufactured starting from the growth of the lower n-type GaN layer. Also in this case, the same effect as described above can be obtained.
[0122]
(Sixth embodiment)
In this embodiment, when a GaN-based compound semiconductor light emitting diode is manufactured according to the method described in the first embodiment, the light emission intensity during operation (current injection) of the formed light emitting diode and the growth after the well layer is formed. N in the carrier gas that flows during the interruption period ₂ Gas and H ₂ The relationship with the mixing ratio with gas will be described.
[0123]
Specifically, in the present embodiment, N is used as the carrier gas that flows during the growth interruption period after the growth of the well layer constituting the light emitting layer. ₂ Gas and H ₂ A light emitting element (light emitting diode) was fabricated in substantially the same manner as the manufacturing method in the first embodiment except that the mixing ratio with the gas was variously changed (however, the total amount of the carrier gas was constant). The growth temperature during the growth of the light emitting layer was set at 750 ° C., and the growth interruption time after the well layer growth was set at 30 seconds.
[0124]
FIG. 13 shows the peak emission wavelength (white circle plot) and the emission intensity (black circle plot) at the peak emission wavelength when a current of 20 mA is injected for the light-emitting diode thus manufactured. ₂ Gas and H ₂ The change with respect to the mixing ratio with gas is shown.
[0125]
From FIG. 13, N in the carrier gas ₂ As the gas ratio decreases, the emission wavelength becomes shorter and the emission intensity at the peak emission wavelength also tends to decrease. This is N ₂ It is considered that the formation of InGaN quantum dots in the well layer is suppressed as the gas decreases, and thereby the quantum effect and the effect of monochromatic emission wavelength from the quantum dots are sufficiently obtained. Therefore, as the carrier gas that flows during the growth interruption period after the well layer growth, nitrogen gas (N ₂ By flowing a gas mainly composed of gas, the peak emission wavelength is lengthened, and the emission intensity at the peak emission wavelength is increased.
[0126]
The results of FIG. 13 are for the case where the growth temperature of the light emitting layer is 750 ° C., but when the growth temperature is set to a higher temperature of about 800 ° C. or when the growth temperature is set to a lower temperature of about 700 ° C. A similar trend was observed.
[0127]
Further, when providing a growth interruption period not only after the growth of the well layer but also after the growth of the barrier layer, the nitrogen gas (N ₂ By flowing a carrier gas mainly composed of a gas, the peak emission wavelength becomes longer, and the emission intensity at the peak emission wavelength tends to increase.
[0128]
The above results are not limited to the case where the number of well layers constituting the light emitting layer is a specific value. In particular, the same effect as described above can be obtained for a multiple quantum well in which the number of well layers is in the range of 2 to 20 layers.
[0129]
In the quantum well structure of the light emitting layer, the same effect as described above can be obtained when there is no barrier layer below (outside) the first well layer or when there is no barrier layer above (outside) the last well layer. can get. Further, the growth conditions of the respective well layers may not be the same, and the growth conditions of the respective barrier layers may not be the same.
[0130]
In the configuration of the present embodiment, a GaN film is used as the low-temperature buffer layer, but instead of this, Al _x Ga _1-x An N (0 ≦ x ≦ 1) layer or a ZnO layer may be used. In these cases, the same effect as described above is obtained.
[0131]
In this embodiment, a sapphire substrate having a (0001) plane is used as the substrate. However, the plane orientation does not have a particularly large effect on the effect of improving the emission intensity, and instead of the sapphire substrate. It has been confirmed that the same effect can be obtained even when other substrates made of GaN, SiC, spinel, mica, or the like are used. Further, when a GaN substrate is used as the substrate, it is not necessary to provide a pretreatment by heat treatment in a hydrogen atmosphere and a low-temperature buffer layer for epitaxial growth of the GaN layer. That is, when a GaN substrate is used, a carrier gas mainly composed of an inert gas and NH _Three Raise temperature in atmosphere, then TMG and / or SiH _Four And a light emitting device can be manufactured starting from the growth of the lower n-type GaN layer. Also in this case, the same effect as described above can be obtained.
[0132]
(Seventh embodiment)
In this embodiment, when a GaN-based compound semiconductor light emitting diode is manufactured according to the method described in the first embodiment, the light emission intensity during operation (current injection) of the formed light emitting diode and the growth after the well layer is formed. Ammonia gas (NH _Three The relationship between the amount of gas) introduced and the length of the growth interruption period (growth interruption time) will be described.
[0133]
Specifically, in the present embodiment, ammonia gas (NH) that flows during the growth interruption period after the growth of the well layer constituting the light emitting layer is formed. _Three A light emitting element (light emitting diode) was fabricated in substantially the same manner as the manufacturing method in the first embodiment, except that the amount of gas) introduced and the growth interruption time were variously changed. The growth temperature during the growth of the light emitting layer was set to 770 ° C. In addition, ammonia gas (NH _Three The amount of gas introduced was set at 5 liters / minute, 3 liters / minute, and 0 liters / minute (ie, no introduction).
[0134]
With respect to the light-emitting diode manufactured by the manufacturing process as described above, the in-plane distribution of the emission wavelength from the light-emitting layer was measured using a microscopic PL having a diameter of 1 μm. FIG. 14 shows the relationship between the reciprocal of the half-value width of the emission wavelength distribution curve and the growth interruption time after the well layer growth as a result of the above measurement. In FIG. 14, ammonia gas (NH _Three The reciprocal of the half-value width in the emission wavelength distribution curve obtained when the amount of gas introduced is 3 liters / minute is normalized to 1.
[0135]
Referring to FIG. 14, NH is placed in the growth reactor during the growth interruption period. _Three Even when no gas was introduced, it was confirmed that the emission wavelength from the quantum dots was monochromatic (that is, the half-value width of the emission wavelength distribution curve was increased) due to the uniformization of the InGaN quantum dots. _Three By introducing the gas, the effect of monochromatic emission wavelength due to the uniformization of the InGaN quantum dots appears more prominently. In addition, NH in the reactor during the growth interruption period _Three By introducing the gas, even if the growth interruption time is made longer, the above-described effect can be realized. Therefore, the growth interruption time can be set longer to facilitate the manufacturing process.
[0136]
The result of FIG. 14 is the case where the growth temperature of the light emitting layer is 770 ° C., but also when the growth temperature is set to a higher temperature of about 800 ° C. or when the growth temperature is set to a lower temperature of about 700 ° C. A similar trend was observed. Moreover, the same tendency as above was observed not only after the well layer was grown but also when the growth interruption period was provided after the growth of the barrier layer.
[0137]
The above results are not limited to the case where the number of well layers constituting the light emitting layer is a specific value. In particular, the same effect as described above can be obtained for a multiple quantum well in which the number of well layers is in the range of 2 to 20 layers.
[0138]
In the quantum well structure of the light emitting layer, the same effect as described above can be obtained when there is no barrier layer below (outside) the first well layer or when there is no barrier layer above (outside) the last well layer. can get. Further, the growth conditions of the respective well layers may not be the same, and the growth conditions of the respective barrier layers may not be the same.
[0139]
In the configuration of the present embodiment, a GaN film is used as the low-temperature buffer layer, but instead of this, Al _x Ga _1-x An N (0 ≦ x ≦ 1) layer or a ZnO layer may be used. In these cases, the same effect as described above is obtained.
[0140]
In this embodiment, a sapphire substrate having a (0001) plane is used as the substrate. However, the plane orientation does not have a particularly large effect on the effect of improving the emission intensity, and instead of the sapphire substrate. It has been confirmed that the same effect can be obtained even when other substrates made of GaN, SiC, spinel, mica, or the like are used. Further, when a GaN substrate is used as the substrate, it is not necessary to provide a pretreatment by heat treatment in a hydrogen atmosphere and a low-temperature buffer layer for epitaxial growth of the GaN layer. That is, when a GaN substrate is used, a carrier gas mainly composed of an inert gas and NH _Three Raise temperature in atmosphere, then TMG and / or SiH _Four And a light emitting device can be manufactured starting from the growth of the lower n-type GaN layer. Also in this case, the same effect as described above can be obtained.
[0141]
Note that the light emitting diode manufactured according to the manufacturing process of the present invention as described in the above several embodiments has a nitride growth layer in which light generated from the light emitting layer 306 is stacked on the substrate 301. It may be a type that transmits in the stacking direction and is emitted to the outside, or a type that transmits light from the side surface or the back surface of the substrate 301 toward the outside. Further, when a conductive substrate is used as the substrate 301, a light emitting diode in which one electrode (for example, the n-type electrode 312b) is formed on the back surface of the substrate 301 can be manufactured. In any case, the same effect as described above can be obtained.
[0142]
【The invention's effect】
As described above, according to the present invention, a GaN-based compound semiconductor light-emitting device composed of a GaN-based compound semiconductor material containing indium is manufactured in the growth process of the well layer and the barrier layer that constitute the light-emitting layer. By setting an appropriate growth time in the growth interruption step, a light emitting element having high light emission efficiency can be manufactured with good uniformity within the substrate surface.
[Brief description of the drawings]
FIG. 1 is a timing chart showing changes in growth temperature and supply amount of each raw material during growth of a light emitting layer and a semiconductor layer in the vicinity thereof in the method for manufacturing a GaN-based compound semiconductor light emitting device of the present invention.
FIG. 2 is a schematic view schematically showing a configuration of a crystal growth apparatus (MOCVD apparatus) used in each embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view schematically showing a configuration of a light-emitting diode as an example of a GaN-based compound semiconductor light-emitting element formed according to the present invention in the first embodiment of the present invention.
FIG. 4 shows a light emitting diode manufactured according to the first embodiment in which the growth temperature of the light emitting layer is set to 780 ° C. and the growth interruption time after the well layer growth is set to 5 seconds. It is a figure which shows the relationship (light emission wavelength distribution curve) with the number of the light emission parts in the light emitting layer which is.
FIG. 5 shows a light emitting diode manufactured according to the first embodiment in which the growth temperature of the light emitting layer is set to 780 ° C. and the growth interruption time after the growth of the well layer is set to 15 seconds. It is a figure which shows the relationship (light emission wavelength distribution curve) with the number of the light emission parts in the light emitting layer which is.
FIG. 6 shows a light emitting diode manufactured according to the first embodiment in which the growth temperature of the light emitting layer is set to 780 ° C. and the growth interruption time after the well layer growth is set to 2 minutes. It is a figure which shows the relationship (light emission wavelength distribution curve) with the number of the light emission parts in the light emitting layer which is.
FIG. 7 shows the inverse of the half-value width of the emission wavelength distribution curve and the growth after the well layer growth in the light-emitting diode manufactured with the growth temperature of the light-emitting layer being 730 ° C., 750 ° C., and 770 ° C. in the first embodiment. It is a figure which shows the relationship with interruption time.
FIG. 8 shows the light emission intensity at the peak light emission wavelength and the growth interruption time after the growth of the well layer in the light emitting diode manufactured at the light emitting layer growth temperatures of 730 ° C., 750 ° C., and 770 ° C. in the first embodiment. It is a figure which shows the relationship.
FIG. 9 shows the reciprocal of the half-value width of the emission wavelength distribution curve and the growth after the well layer growth in the light-emitting diode manufactured with the growth temperature of the light-emitting layer being 770 ° C., 790 ° C., and 810 ° C. in the first embodiment. It is a figure which shows the relationship with interruption time.
FIG. 10 shows the emission intensity at the peak emission wavelength and the growth interruption time after the growth of the well layer in the light emitting diode manufactured at the light emitting layer growth temperatures of 770 ° C., 790 ° C., and 810 ° C. in the first embodiment. It is a figure which shows the relationship.
FIG. 11 is a schematic cross-sectional view schematically showing a configuration of a semiconductor laser as an example of a GaN-based compound semiconductor light-emitting element formed according to the present invention in the second embodiment of the present invention.
FIG. 12 shows the reciprocal of the half-value width of the emission wavelength distribution curve and the growth after the well layer growth in the light-emitting diode manufactured with the growth temperature of the light-emitting layer being 730 ° C., 770 ° C., and 810 ° C. in the fifth embodiment. It is a figure which shows the relationship with interruption time.
FIG. 13 shows the N in the gas supplied during the growth interruption period for the light emitting diode fabricated in the sixth embodiment. ₂ It is a figure which shows the relationship between the ratio of gas, the peak emission wavelength, and the emission intensity in a peak emission wavelength.
FIG. 14 shows NH in the gas supplied during the growth interruption period in the seventh embodiment. _Three It is a figure which shows the relationship between the reciprocal number of the half value width of the light emission wavelength distribution curve, and the growth interruption time after well layer growth in the light emitting diode produced by changing the introduction amount of gas.
FIG. 15 is a schematic cross-sectional view schematically showing another configuration of a semiconductor laser as an example of a GaN-based compound semiconductor light-emitting element formed according to the present invention in the second embodiment of the present invention.
[Explanation of symbols]
101a, 101b, 101c Growth interruption period after well layer formation
102a, 102b, 102c, 102d Barrier layer growth period
103a, 103b, 103c Well layer growth period
104 n-type GaN layer growth period
105 p-type GaN layer growth period
106 Sublimation prevention layer growth period
107 Temperature drop period
108 Heating period

Claims (13)

A method of manufacturing a GaN-based compound semiconductor light emitting device,
For m = 1, 2,..., n, a step of crystal-growing a barrier layer made of a GaN-based compound semiconductor containing indium and m-th barrier layer, and m on the m-th barrier layer And repeating the step of crystal growth of the well layer made of a GaN-based compound semiconductor containing indium and then the n-th well layer and being a n + 1-th barrier layer on the n-th well layer. Including a step of forming a light emitting layer having a quantum well structure including an n + 1 barrier layer and an n well layer by crystal growth of a barrier layer made of a compound semiconductor,
In the step of crystal growth of the m-th well layer, after completion of crystal growth of the m-th well layer, a growth interruption for a first predetermined time is performed,
In the step of crystal growth of the mth barrier layer, after the completion of crystal growth of the mth barrier layer, the growth interruption for a second predetermined time is performed, n is a natural number of 1 or more, and m is A method for manufacturing a GaN-based compound semiconductor light-emitting element, which is a natural number satisfying 1 ≦ m ≦ n. A method of manufacturing a GaN-based compound semiconductor light emitting device,
A step of crystal-growing a first well layer made of a GaN-based compound semiconductor containing indium;
with respect to m = 2,..., n, a step of crystal-growing a barrier layer made of a GaN-based compound semiconductor containing indium on the m−1th well layer, and m The n-1 barrier layer and the n well layer are repeated by repeating the step of crystal growth of the mth well layer, which is a well layer made of a GaN-based compound semiconductor containing indium, on the second barrier layer. Forming a light emitting layer having a quantum well structure including:
Including
In the step of crystal growth of the first or m-th well layer, after completion of crystal growth of the first or m-th well layer, a growth interruption for a first predetermined time is performed,
In the step of crystal growth of the mth barrier layer, after the completion of crystal growth of the mth barrier layer, the growth interruption for a second predetermined time is performed, n is a natural number of 1 or more, and m is A method for manufacturing a GaN-based compound semiconductor light-emitting element, which is a natural number satisfying 2 ≦ m ≦ n. A step of crystal-growing a first barrier layer made of a GaN-based compound semiconductor containing indium, wherein the first well layer is formed on the first barrier layer; The manufacturing method of the GaN-type compound semiconductor light-emitting device of Claim 2. a step of crystal-growing a barrier layer made of a GaN-based compound semiconductor containing indium that is an (n + 1) th barrier layer, wherein the (n + 1) th barrier layer is formed on the nth well layer; The manufacturing method of the GaN-type compound semiconductor light-emitting device of Claim 2. 5. The method for manufacturing a GaN-based compound semiconductor light-emitting element according to claim 1, wherein nitrogen gas is introduced during the first predetermined period of time during which growth is interrupted. The method for manufacturing a GaN-based compound semiconductor light-emitting element according to claim 1, wherein the first predetermined time is set in a range of 10 seconds to 100 seconds. The light emitting layer of the growth temperature is 730 ° C. to 750 when in the range of ° C. or less 90 seconds before Symbol first predetermined time more than 10 seconds,
The light emitting layer of the growth temperature is 750 ℃ ~770 predetermined time before Symbol first if the range of ° C. 80 seconds 10 seconds or less,
The growth temperature of the light emitting layer 770 ℃ ~790 predetermined time before Symbol first if the range of ° C. 60 seconds 10 seconds or less,
The growth temperature of the light emitting layer is a predetermined time before Symbol first if the range of 790 ℃ ~810 ℃ is set in a range of 50 seconds or less 10 seconds or more, any one of claims 1 to 5 method of manufacturing a GaN-based compound semiconductor light emitting device according to. 5. The method of manufacturing a GaN-based compound semiconductor light-emitting element according to claim 1, wherein the second predetermined time is set in a range of 1 second to 60 minutes. The growth at the time of interruption, carrier gas flow mainly comprising nitrogen gas, a method of manufacturing a GaN-based compound semiconductor light-emitting device according to any one of claims 1 to 8. Wherein the time growth is interrupted, the nitrogen gas mainly flows a carrier gas of hydrogen gas are mixed, a method of manufacturing a GaN-based compound semiconductor light-emitting device according to any one of claims 1 to 8. Wherein the carrier gas together with, flow V group material gas, a method of manufacturing a GaN-based compound semiconductor light-emitting device according to claim 9 or 10. In the step of forming the light emitting layer, flow SiH ₄ during the formation of the barrier layer, the method of manufacturing a GaN-based compound semiconductor light-emitting device according to any one of claims 1 to 11. In the step of forming the light emitting layer, flow SiH ₄ during formation of the well layer, a method of manufacturing a GaN-based compound semiconductor light emitting device according to claim 12.

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