KR20140099693A - Non-polar nitride-based light emitting device and method for manufacturing the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly, to a non-polarization nitride based light emitting device and a manufacturing method thereof. The present invention provides a semiconductor device comprising: a first semiconductor layer of a first conductivity type including an a-plane or m-plane nitride-based semiconductor; A second semiconductor layer located on the first semiconductor layer and including a non-doped nitride based semiconductor; And a nitride based semiconductor having a first thickness and comprising indium to emit light of a first emission wavelength, the first thickness being located on the second semiconductor layer, wherein the first thickness is a c-plane nitride for emitting the first emission wavelength An active layer thicker than the semiconductor; A third semiconductor layer located on the active layer and including an undoped nitride-based semiconductor; And a second conductive fourth semiconductor layer located on the third semiconductor layer and including a nitride based semiconductor.

Description

[0001] The present invention relates to a non-polarized nitride light emitting device and a manufacturing method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly, to a non-polarization nitride based light emitting device and a manufacturing method thereof.

Gallium nitride used as a material of a semiconductor device such as a blue light-emitting diode is a material having a hexagonal crystal structure, and a thin film is grown mainly in the crystal direction of the c-plane. This is because the case of growing in the crystal direction of the c-plane facilitates horizontal growth, and a thin film of high quality with few defects such as dislocations can be obtained.

At this time, when the growth direction is taken as a reference, the nitride layer and the gallium layer are crossed and repeated on the same plane. There is a strong internal field between nitrogen and gallium, which causes polarization.

The inner field formed is divided into two components, spontaneous polarization and piezo-electric field. When a layer having different lattice constants such as an InAlGaN material is inserted, the polarization effect increases, A quantum confined Stark effect may occur.

For example, in a structure in which a gallium aluminum indium gallium nitride (InAlGaN) active layer is inserted between p-type and n-type gallium nitride (GaN) layers as in a blue light emitting diode, deformation occurs between layers due to difference in lattice constant, An internal field may be generated to cause bending of the active layer energy band structure.

As a result, the wave function of electrons and holes in the active layer is spatially separated and the size of the energy gap is also reduced. This phenomenon can be a major cause of deterioration of recombination efficiency of injected electrons and positive space.

Therefore, in a light emitting diode using a gallium nitride-based material grown in the c-axis direction, in order to prevent the stress caused by the heteroepitent film from deteriorating the performance of the device, the thickness of the InAlGaN heteroepitent thin film layer is designed not to exceed about 3 nm It is common.

In addition, in the gallium nitride-based light emitting diode, there is an efficiency-droop phenomenon as the applied current is increased, which is known to be caused by the thin thickness of the active layer.

SUMMARY OF THE INVENTION The present invention provides a non-polarization nitride based light emitting device capable of improving crystal quality of an active layer in a non-polarization nitride based light emitting device and a method of manufacturing the same.

According to a first aspect of the present invention, there is provided a semiconductor device comprising: a first semiconductor layer of a first conductivity type including an a-plane or m-plane nitride-based semiconductor; A second semiconductor layer located on the first semiconductor layer and including a non-doped nitride based semiconductor; And a nitride based semiconductor having a first thickness and comprising indium to emit light of a first emission wavelength, the first thickness being located on the second semiconductor layer, wherein the first thickness is a c-plane nitride for emitting the first emission wavelength An active layer thicker than the semiconductor; A third semiconductor layer located on the active layer and including an undoped nitride-based semiconductor; And a second conductive fourth semiconductor layer located on the third semiconductor layer and including a nitride based semiconductor.

Here, the first thickness of the active layer may be 5 nm to 15 nm.

The first thickness of the active layer may be two to ten times as thick as the c-plane nitride semiconductor for emitting the first emission wavelength.

Here, between the active layer and the third semiconductor layer, a cap layer including a nitride-based semiconductor for preventing the volatilization of indium in the active layer may be further included.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: growing a first semiconductor layer including a first conductive nitride-based semiconductor including a first type dopant on a substrate; Growing a second semiconductor layer on the first semiconductor layer including a nitride-based semiconductor that does not include a dopant at a first temperature; Growing an active layer on the second semiconductor layer including a nitride-based semiconductor containing indium at a second temperature lower than the first temperature; Annealing the active layer at a third temperature higher than the second temperature; Growing a third semiconductor layer including a nitride-based semiconductor that does not include a dopant on the active layer; And growing a fourth semiconductor layer including a second conductive nitride-based semiconductor including a second-type dopant on the third semiconductor layer.

Here, at least one of the first semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer may be grown at the first temperature.

Here, the third temperature may be between the second temperature and the first temperature.

Here, after the active layer is grown, a step of growing a cap layer including a nitride-based semiconductor on the active layer may be further included.

The step of growing the cap layer may be grown at the second temperature.

At this time, the cap layer may be for preventing the volatilization of the indium.

Here, the active layer has a nitride-based semiconductor having a first thickness including indium so as to emit light having a first emission wavelength, and the first thickness is thicker than the c-plane nitride-based semiconductor for emitting the first emission wavelength .

At this time, the first thickness of the active layer may be 5 nm to 15 nm.

On the other hand, the third temperature may be higher than the second temperature by 20 ° C to 400 ° C.

The present invention has the following effects.

First, in a non-polarization nitride based semiconductor light emitting device using a homogenous or heterogeneous substrate, a heat treatment process after growth of an active layer including indium gallium nitride (InGaN) is employed to significantly reduce crystal defects generated in the growth process of the InGaN thin film, It is possible to improve the light emitting recombination efficiency performance.

Particularly, the In composition is effectively controlled through the heat treatment process after the growth of the InGaN thin film in the nonpolarized gallium nitride semiconductor such as the a-plane and the m-plane in which the draw-in property of indium (In) is lower than that of the c- can do.

Thus, problems such as generation of stress due to an increase in the thickness of the InGaN thin film can be alleviated through the heat treatment process after the growth of the InGaN thin film, thereby contributing to the improvement of the performance of the light emitting device.

1 is a flow chart showing an example of a process for manufacturing a polarization-free nitride-based light emitting device.
2 is a schematic view showing a manufacturing process of a non-polarization nitride based light emitting device together with a growth temperature.
3 is a cross-sectional view showing an example of a non-polarization nitride based light emitting device.
4 is a graph showing the emission wavelength of the active layer according to the growth temperature for each crystal direction of gallium nitride.
FIG. 5 is a transmission electron microscopy (TEM) image of the non-polarization a-plane InGaN active layer 231 grown on the second semiconductor layer by a conventional method.
6 is a graph showing EL (Electro-Luminescence) measurement results of a non-polarized a-plane light emitting diode manufactured by a conventional method.
7 is a TEM (Transmission Electron Microscopy) image of the non-polarization a-plane InGaN active layer 231 grown on the second semiconductor layer according to the present invention.
FIG. 8 is a graph showing EL (Electro-Luminescence) measurement results of a non-polarized a-plane light emitting diode fabricated according to the present invention.
9 and 10 are cross-sectional TEM images and simulation diagrams of the InGaN thin films before and after the heat treatment process.
11 is a graph comparing PL (Photo-Luminescence) characteristics in different InGaN active layer heat treatment conditions.
12 and 13 are graphs showing capacitance-voltage measurement results of a non-polarized a-plane light emitting diode according to the presence or absence of the active layer heat treatment process.
FIGS. 14 and 15 are flowcharts showing other examples of a process for manufacturing a polarization-free nitride-based light emitting device.
16 is a graph showing the external quantum efficiency characteristic according to the application of current to the polarized-nitride light emitting device.
17 is a graph showing the external quantum efficiency characteristic according to the current application of the non-polarization nitride based light emitting device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

The non-polarization nitride-based semiconductor means a crystal material having no polarization phenomenon in the growth direction, and can be realized by growing in a direction rotated in the 90 ° direction with the c-plane. Here, the nitride-based semiconductor is formed of a semiconductor such as gallium nitride (GaN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum indium gallium nitride (AlInGaN), indium nitride (InN) It can mean.

In this case, when the growth direction is taken as a reference, for example, since the nitrogen layer and the gallium layer have the same number in the plane, the internal field in the growth direction is canceled and the polarization characteristic does not appear. Therefore, distortion of the energy band due to the piezoelectric polarization of the conventional c-plane gallium nitride does not occur, and the problems such as reduction of recombination efficiency of electrons and holes in the active layer can be improved.

Unlike the c-plane gallium nitride-based material, which is limited in the active layer design to a certain thickness or less, the thickness limitation can be largely mitigated and the active layer design suitable for high current driving can be realized. Until now, a heterogeneous substrate can be used for growing the thin film of the non-polarized gallium nitride. For example, a technique of growing an a-plane or m-plane gallium nitride on an r-plane sapphire substrate is utilized.

The photovoltaic efficiency of a light emitting diode is roughly composed of three kinds of efficiencies. An internal quantum efficiency indicating how much electrons injected from the outside of the active layer are converted into photons by light emission recombination and a degree of emission of the generated photons to the outside of the light emitting diode Light extraction efficiency, and injection efficiency, which represents the voltage drop due to the series resistance component.

Hereinafter, in the thin film growth of the non-polarization nitride based semiconductor using the above-mentioned heterogeneous substrate, a nitride-based semiconductor material such as an a-plane or m-plane gallium nitride may be grown on a r-plane sapphire substrate. The manufacturing process of the non-polarization nitride based light emitting device manufactured by the above process will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flow chart showing an example of a process of manufacturing a non-polarization nitride based light emitting device, and FIG. 2 is a schematic view showing a manufacturing process of a non-polarization nitride based light emitting device together with a growth temperature. FIG. 3 is a cross-sectional view showing an example of a nonpolar nitride-based light emitting device manufactured by such a process. Hereinafter, a non-polarization nitride based light emitting device and a manufacturing method thereof will be described with reference to FIGS. 1 to 3. FIG.

As described above, the non-polarization nitride based light emitting device can be fabricated on the substrate 100 including a different substrate such as sapphire.

Such a substrate 100 uses a substrate 100 having a crystal plane capable of growing a non-polar nitride-based semiconductor, and an r-plane ([1-102] plane) sapphire substrate can be used.

It goes without saying that various substrates having other non-polarization can be used. That is, a substrate such as a-plane silicon carbide (SiC), m-plane SiC, spinel or the like may be used, or a gallium nitride homogeneous substrate may be used.

Further, such a substrate 100 may include a buffer layer (not shown) including a nitride-based semiconductor.

Such a non-polarization nitride based light emitting device includes a multi-layered nitride-based semiconductor layer 200 having an a-plane or m-plane crystal orientation. The nitride based semiconductor layer 200 can be grown by MOCVD (Metal-Organic Chemical Vapor Deposition), MBE (Molecular Beam Epitaxy), HVPE (Hydride Vapor Phase Epitaxy) .

First, a first semiconductor layer 210 including a first conductive nitride-based semiconductor including a first-type dopant is grown on the substrate 100 (S10). The first semiconductor layer 210 may include gallium nitride (GaN).

Here, the first conductivity may be n-type, and silicon (Si) or germanium (Ge) may be used as the first type dopant.

The nitride-based semiconductor thin film including the first semiconductor layer 210 is formed by a chemical reaction of NH ₃ with an organic metal source such as TMG (Tri-Methyl Gallium) or TEG (Tri-Ethyl Gallium) It grows. Such thin film growth can be performed in nitrogen (N ₂ ) or hydrogen (H ₂ ) atmosphere.

Then, a second semiconductor layer 220 including a nitride-based semiconductor that does not include a dopant is grown on the first semiconductor layer 210 at a first temperature (S20). That is, the second semiconductor layer 220 includes a nitride-based semiconductor that is not intentionally doped. The second semiconductor layer 220 may include gallium nitride (GaN).

Next, the active layer 230 including indium (In) is grown by lowering the growth temperature to a second temperature lower than the first temperature on the second semiconductor layer 220 (S30). That is, the active layer 230 may include indium gallium nitride (InGaN). At this time, TMI (Tri-Methyl Indium) may be used as the indium source.

Here, the active layer 230 includes a nitride semiconductor of a first thickness including indium to emit light of a first emission wavelength. The active layer 230 may be composed of a single quantum well, and the first thickness represents the thickness of a single quantum well.

The active layer 230 may be formed to have an emission wavelength of usually 440 nm. For this, as described above, the active layer 230 may be formed of InGaN having a first thickness.

At this time, the first thickness may be thicker than the polar nitride semiconductor for emitting the first emission wavelength. That is, it can be made thicker than the active layer 230 including the c-plane nitride-based semiconductor.

For example, the first thickness of the active layer 230 may be between 5 nm and 15 nm. In this way, the active layer 230 can be grown with a thick thickness, and phenomena such as efficiency droop according to the amount of current of the polar nitride-based semiconductor can be improved. This will be described in detail below.

Thereafter, a process (S40) of heat-treating the active layer 230 by raising the temperature in the growth equipment to a third temperature higher than the second temperature is performed.

At this time, the supply of Group III source such as TMG or TEG or TMI is stopped, and NH _{3, which} is a source of Group V, is continuously supplied to the reaction chamber. The third temperature for the heat treatment may be in a temperature range higher than the growth temperature of the active layer 230 by about 20 ° C to 400 ° C.

The cap layer 260 including the nitride-based semiconductor may be grown on the active layer 230 (S31) after the growth of the active layer 230 prior to the heat treatment process S40.

The step S31 of growing the cap layer 260 can be performed at a second temperature which is a growth temperature of the active layer 230. [

At this time, the cap layer 260 may be to prevent volatilization of indium. That is, the cap layer 260 may be formed of a gallium nitride (GaN) layer to prevent the indium from being volatilized in the active layer 230 by increasing the temperature after the growth of the active layer 230.

Next, a third semiconductor layer 240 including a nitride-based semiconductor that does not contain a dopant is grown on the active layer 230 (S50). That is, the third semiconductor layer 220 includes a nitride-based semiconductor that is not intentionally doped. The third semiconductor layer 220 may include gallium nitride (GaN).

The third semiconductor layer 240 may be grown at a first temperature such as the second semiconductor layer 220. As shown in FIG. 2, the first temperature may be higher than the third temperature, which is a process of heat-treating the active layer 230.

However, the third temperature for the heat treatment may be equal to the first temperature, and in some cases, the third temperature may be higher than the first temperature.

Thereafter, a fourth semiconductor layer 250 including a second conductive nitride-based semiconductor including a second-type dopant is grown on the third semiconductor layer 240 (S60).

The first semiconductor layer 210 may include gallium nitride (GaN). Here, the second conductivity may be p-type, and a material such as magnesium (Mg) may be used for the second type dopant.

As described above, the first semiconductor layer 210 including the n-type nitride semiconductor, the second semiconductor layer 220, the active layer 230, the p-type The third semiconductor layer 240 including the nitride semiconductor, and the fourth semiconductor layer 250 may be grown in this order to form the nitride semiconductor layer 200 for the light emitting diode.

The non-polarization nitride based light emitting device manufactured by such a structure includes a first electrode (not shown) electrically connected to the first semiconductor layer 210 and a second electrode electrically connected to the fourth semiconductor layer 250 (Not shown) to emit light.

Electrons and holes are injected from the first semiconductor layer 210 of the n-type and the fourth semiconductor layer 250 of the p-type, respectively, and are recombined with each other by light emission recombination between the carriers in the active layer 230 As shown in FIG.

Therefore, the light emitting recombination efficiency of the active layer 230 determines the performance of the device, and it is required to optimize the design so as to have excellent crystal quality of the active layer 230 and excellent carrier injection characteristics.

In general, the a-plane or m-plane nonpolarized gallium nitride-based material has a lower In draw-in characteristic than the c-plane. In the light emitting device of the visible light region, a nitride based semiconductor material such as gallium nitride (GaN) containing In is used as the active layer 230. Thin film growth is performed by controlling the In composition so that light of a specific wavelength is emitted.

FIG. 4 shows the emission wavelength of the active layer depending on the growth temperature of each gallium nitride crystal. When the same growth temperature is used as a reference, the nonpolarized gallium nitride based material such as m-plane exhibits polarization in the c- Polarity) exhibits a low emission wavelength as compared with a gallium nitride semiconductor or a semi-polarizing material.

This is because there is no reduction in the energy gap due to the low In introduction of the nonpolarized gallium nitride semiconductor and the piezoelectric polarization occurring in other structures. That is, in order to fabricate a light emitting diode having the same wavelength, there is a relatively difficulty in thin film growth, such as lowering the growth temperature of the thin film of gallium nitride layer containing In.

However, at the thin film growth temperature, there is a high possibility of crystal quality problems such as defect generation, which may result in inferior performance compared to c-plane light emitting diodes.

FIG. 5 shows TEM (Transmission Electron Microscopy) images of the active layer 231 grown on the second semiconductor layer 220, that is, the non-polarization a-plane InGaN layer.

This is an example in which the active layer 231 including the InGaN thin film of about 11 nm thickness is grown on the second semiconductor layer 220 including the a-plane GaN, nm thick. In FIG. 5, the first semiconductor layer 210 may be present together with the second semiconductor layer 220.

As can be seen from FIG. 5, the surface roughness increases greatly due to the increase of the thickness of the InGaN layer, local segregation of In may occur, and a remarkable determination such as generation of misfit dislocation of very high density It can be seen that the quality deteriorates.

FIG. 6 shows EL (Electro-Luminescence) measurement results of a non-polarized a-plane light emitting diode manufactured by a conventional method.

In the graph of FIG. 6, it can be seen that light emission occurs in two wavelength regions. In low-current driving, long-wavelength light emission dominates and light emission in a region near 435 nm is leading to increase of current application.

This characteristic can be attributed to the crystal quality of the low-level InGaN active layer thin film. That is, it can be assumed that the driving characteristic at low current is determined by In localization due to In segregation or clustering phenomenon.

On the other hand, FIG. 7 shows a TEM (Transmission Electron Microscopy) image in which an active layer 230 including an InGaN thin film with a thickness of about 11 nm is grown on a second semiconductor layer 220 including a-plane GaN .

As described above, this thin film shows a state after the heat treatment process is performed after the growth of the active layer 230. The conditions of the active layer 230 are as described above,

That is, since the active layer 230 has a thickness of about 11 nm, the active layer 230 has grown to be three times thicker than the thickness of about 3 nm used for the active layer in the c-plane light emitting diode. The annealing process is performed in a temperature range of about 20 ° C to about 400 ° C higher than the growth temperature of the active layer 230.

In comparison with FIG. 5, it can be seen that the roughness of the surface and the aggregation of In are significantly improved by the TEM measurement compared with the thin film which was not subjected to the heat treatment. This is because the low growth temperature, The crystal quality problem of the non-polarization InGaN material can be solved by post-growth annealing process.

FIG. 8 shows EL (Electro-Luminescence) measurement results of a non-polarized a-plane light emitting diode fabricated through a manufacturing process including the above-described heat treatment process.

Compared to FIG. 6, it can be seen that the long wavelength emission disappears in the low current drive, and only the emission in the region near 435 nm appears.

FIGS. 9 and 10 are cross-sectional TEM images of InGaN thin films before and after the heat treatment process and comparison of the misfit dislocation distributions obtained through simulation.

9A shows a cross-sectional TEM image of an InGaN thin film constituting an active layer before a heat treatment process, and FIG. 9B shows a simulation of a misfit dislocation with respect to a portion A in FIG. 9A. 10 (a) shows a cross-sectional TEM image of the InGaN thin film constituting the active layer before the heat treatment step, and FIG. 10 (b) shows a simulation of the mispit potential with respect to the portion B in FIG. 10 (a).

As shown in the drawing, the roughness of the surface is greatly improved as compared with the thin film before heat treatment, and it is confirmed that the uneven distribution of the stress caused by the clustering of In is greatly alleviated over the entire region of the thin film .

In the TEM image of Figs. 9 (a) and 10 (a), the dense portion is a region having a relatively large stress and is caused by a difference in the composition of the local In.

In the simulation results of Figs. 9 (b) and 10 (b), the C portion represents the region where the misfitted potential is generated. As can be seen from the above, it can be seen that the thin film before the heat treatment has a large number of misfit dislocations, but the density of the dislocations remarkably decreases after the heat treatment.

11 is a graph comparing PL (Photo-Luminescence) characteristics in different InGaN active layer heat treatment conditions. At this time, the difference in the PL intensity can be regarded as the light emitting recombination efficiency of the active layer 230 according to the respective process conditions, so that the heat treatment conditions are designed in such a range that the PL intensity is maximized.

12 and 13 show capacitance-voltage (C-V) measurement results of a non-polarized a-plane light emitting diode with and without an active layer heat treatment process.

C-V measurements were performed at various frequencies, where the measured capacitance is frequency dependent.

The decrease in capacitance in the high frequency measurement is due to the limitation of the transfer of the defective charge, and as the frequency dependency increases, the crystal defect in the active layer is in a state of many defects.

As shown in FIGS. 12 and 13, the frequency dependency changes to a large value before and after the heat treatment, and the frequency dependency is remarkably reduced in the light emitting diode including the heat treatment process. This means that crystal defects are greatly reduced.

Fig. 14 is a schematic view showing another example of a manufacturing process of a non-polarization nitride based light emitting device, in which a manufacturing process is shown together with a growth temperature. The structure manufactured according to this manufacturing method is the same as that shown in Fig.

In this example, in the active layer 230 including InGaN, the growth temperature of the active layer 230 can be adjusted to maintain the composition of the In component uniformly.

Usually, as the growth of the InGaN layer continues, the stress in the thin film gradually increases.

At this time, the amount of In drawn into the active layer 230 is affected by the stress on the surface, and an In pulling effect is generated in which the In composition increases as the thin film growth continues. That is, in order to maintain a uniform In composition in the entire region of the thin film, it is advantageous to make In less than in the initial growth.

Accordingly, as shown in FIG. 14, by gradually increasing the growth temperature while maintaining other growth conditions, In can be introduced less at the beginning of the growth of the active layer 230.

Further, as shown in FIG. 15, the In pulling effect can be made to correspond to the In pulling effect by gradually decreasing the flow rate of TMI, which is an In source, while the other growth conditions remain unchanged.

Other conditions are the same as those described with reference to Figs. 1 to 3.

By using such a method, it is possible to control the energy barrier structure of the quantum well in a square shape by minimizing the degree of unevenness of the In composition in the region inside the thick active layer 230.

As described above, a polarity or polarization-type nitride-based light-emitting device has an efficiency-droop phenomenon in which the efficiency decreases gradually when the current application amount increases and becomes equal to or greater than a constant current amount. This is known to be due to a thin active layer.

That is, as shown in FIG. 16, the slope of the light intensity (rectangular dot) tends to decrease gradually as the current increases, and the external quantum efficiency (one dot) gradually decreases.

However, in the non-polarization nitride based light emitting device according to the present invention, the thickness and the internal field of the relatively thick active layer are eliminated and the luminescence is continuously increased according to the application of the electric current.

FIG. 17 is a graph showing the characteristics of the non-polarization nitride based light emitting device according to the present invention. As shown in FIG. 17, the dependency of the external quantum efficiency on the electric current and the electric power is greatly improved . In Fig. 17, the quadrangle represents the optical power and the triangle represents the external quantum efficiency.

As shown in the figure, it can be seen that the optical output increases linearly with respect to the current without decreasing the slope, and the external quantum efficiency exhibits a constant tendency within a certain range without being greatly reduced.

As described above, according to the present invention, in a non-polarized nitride based semiconductor light emitting device using the same or different substrates, a heat treatment process is performed after the growth of the active layer including InGaN, whereby crystal defects The efficiency of the light emitting recombination efficiency of the active layer can be improved.

Particularly, the In composition can be effectively controlled through a heat treatment process after growth of an InGaN thin film in a nonpolarized gallium nitride semiconductor such as an a-plane and an m-plane, in which the draw-in characteristics of In are lower than those of a c-plane gallium nitride semiconductor .

As described above, problems such as generation of stress due to an increase in the thickness of the InGaN thin film can be alleviated through the heat treatment step after the growth of the InGaN thin film, thereby contributing to the improvement of the performance of the light emitting device.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: substrate 200: nitride-based semiconductor layer
210: first semiconductor layer 220: second semiconductor layer
230: active layer 240: third semiconductor layer
250: fourth semiconductor layer 260: cap layer

Claims (13)

a first conductive first semiconductor layer comprising an a-plane or m-plane nitride-based semiconductor;
A second semiconductor layer located on the first semiconductor layer and including a non-doped nitride based semiconductor;
And a nitride based semiconductor having a first thickness and comprising indium to emit light of a first emission wavelength, the first thickness being located on the second semiconductor layer, wherein the first thickness is a c-plane nitride for emitting the first emission wavelength An active layer thicker than the semiconductor;
A third semiconductor layer located on the active layer and including an undoped nitride-based semiconductor; And
And a second conductive fourth semiconductor layer located on the third semiconductor layer and including a nitride based semiconductor. The device according to claim 1, wherein the active layer has a first thickness of 5 nm to 15 nm. The non-polarization nitride based light emitting device according to claim 1, wherein the first thickness of the active layer is 2 to 10 times larger than the c-plane nitride semiconductor for emitting the first emission wavelength. The nonpolar nitride-based light emitting device according to claim 1, further comprising a cap layer between the active layer and the third semiconductor layer, the cap layer including a nitride-based semiconductor for preventing indium from volatilizing in the active layer. Growing a first semiconductor layer comprising a first conductive nitride-based semiconductor comprising a first type dopant on a substrate;
Growing a second semiconductor layer on the first semiconductor layer including a nitride-based semiconductor that does not include a dopant at a first temperature;
Growing an active layer on the second semiconductor layer including a nitride-based semiconductor containing indium at a second temperature lower than the first temperature;
Annealing the active layer at a third temperature higher than the second temperature;
Growing a third semiconductor layer including a nitride-based semiconductor that does not include a dopant on the active layer; And
And growing a fourth semiconductor layer including a second conductive nitride-based semiconductor including a second-type dopant on the third semiconductor layer. The method for manufacturing a non-polarization nitride based light emitting device according to claim 1, . 6. The method of claim 5, wherein at least one of the first semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer is grown at the first temperature. 6. The method of claim 5, wherein the third temperature is between the second temperature and the first temperature. 6. The method of claim 5, further comprising growing a cap layer including a nitride-based semiconductor on the active layer after growing the active layer. 9. The method of claim 8, wherein growing the cap layer comprises growing the cap layer at the second temperature. 9. The method of claim 8, wherein the cap layer prevents the indium from being volatilized. 6. The nitride semiconductor light emitting device according to claim 5, wherein the active layer has a nitride semiconductor of a first thickness including indium to emit light of a first emission wavelength, Nitride-based semiconductor is thicker than the nitride-based semiconductor. 12. The method of claim 11, wherein the first thickness of the active layer is 5 nm to 15 nm. 6. The method of claim 5, wherein the third temperature is higher than the second temperature by 20 ° C to 400 ° C.

Images