JP2000277441A - Semiconductor structure, semiconductor device having the same, and crystal growth method - Google Patents

Abstract

(57) Abstract: A gallium nitride-based compound semiconductor having good crystallinity can be grown so that an element can be formed on a silicon substrate. As a result, a semiconductor element formed on a silicon substrate can be formed. Provided are a semiconductor structure capable of achieving high performance and high reliability, a semiconductor device having the same, and a crystal growth method. SOLUTION: In a semiconductor structure in which a first semiconductor layer 3 made of a gallium nitride-based compound semiconductor is formed on a silicon substrate 1, a high melting point is formed between the silicon substrate 1 and the first semiconductor layer 3. The second semiconductor layer 2 made of a material is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor structure, a semiconductor device having the same, and a method for growing a crystal, and more particularly, to improving the surface flatness and crystallinity of a gallium nitride-based compound semiconductor layer on a silicon substrate. The present invention relates to a semiconductor structure capable of improving the performance of a gallium nitride-based compound semiconductor device, a semiconductor device having the same, and a crystal growth method.

[0002]

2. Description of the Related Art Conventionally, in a gallium nitride-based compound semiconductor, it is difficult to grow a lattice-matched GaN bulk crystal or the like on a GaN substrate, and a GaN substrate cannot be expected. There is adopted a method of growing the film through a buffer layer thereon. This buffer layer is made of AlN or GaN having a thickness of several
It is obtained by growing at a growth temperature of 0 ° C. or lower and then performing heat treatment.

Meanwhile, a sapphire substrate is an insulator and has poor cleavage. Therefore, when an insulating substrate is used for a light-emitting element, there is a problem that the electrode structure is complicated, and there is also a problem that it is difficult to cleave since cleavage is difficult. Therefore, it is desired that a semiconductive or conductive substrate having cleavage be used as a growth substrate. If a silicon substrate can be used as a growth substrate, there is an advantage that it is easy to form a chip because of its good cleavage property, and the electrode structure can be simplified because it is a semiconductive or conductive substrate. Further, since the silicon substrate is cheaper than the sapphire substrate, the cost of the product can be reduced, which is preferable in business.

[0004]

By the way, a growth method similar to that of a sapphire substrate is applied to a silicon substrate, and an A film having a film thickness of several tens nm deposited on a silicon substrate at 900 ° C. or lower.
When a buffer layer is formed by heat-treating 1N and GaN, and a gallium nitride-based compound semiconductor is grown on the buffer layer,
Polycrystals appear on the surface, and it is very difficult to grow a gallium nitride-based compound semiconductor on a silicon substrate. Therefore,
It has been difficult to obtain a gallium nitride-based compound semiconductor thin film having good crystallinity so that a semiconductor element can be formed using a silicon substrate.

The present invention has been made in view of the above circumstances, and a gallium nitride-based compound semiconductor having good crystallinity so that an element can be formed on a silicon substrate can be grown. It is an object of the present invention to provide a semiconductor structure capable of improving the performance and reliability of a semiconductor element formed on a silicon substrate, a semiconductor element having the same, and a crystal growth method.

[0006]

Means for Solving the Problems The present inventors have conducted many experiments and obtained the following findings. Al having a thickness of several tens nm deposited on a silicon substrate at 900 ° C. or less.
It has been found that when N and GaN are subjected to a heat treatment up to about 1000 ° C., dents occur in the silicon substrate. This process is described as follows. A deposited below 900 ° C
1N and GaN have unstable bonds. Therefore, 90
AlN and GaN deposited at 0 ° C. or less are thermally decomposed to some extent during heat treatment to become A1 and Ga.

[0007] These Al and Ga react with silicon by heat treatment to form an alloy.
) Is equal to or higher than the melting point of the alloy, so that the alloyed portion becomes liquid, evaporates while gradually expanding, and causes a depression on the silicon substrate. The gallium nitride-based compound semiconductor grown on the top is further liquefied by liquefaction and evaporation of the alloyed part during the heat treatment, and the liquefied part reacts with the nitrogen source in the growth atmosphere. Then, a polycrystalline gallium nitride-based compound semiconductor is generated.

The inventors of the present invention have conducted intensive studies in view of the above experimental results. As a result, the inventors have found that a high melting point material that does not thermally decompose at about 1000 ° C., which is the growth temperature of a gallium nitride-based compound semiconductor, is used. The inventors have found that the problem can be solved, and have reached the present invention. That is, in the semiconductor structure according to claim 1 of the present invention, a first semiconductor layer formed of a gallium nitride-based compound semiconductor is formed on a silicon substrate. A second layer made of a high melting point material
Characterized in that the semiconductor layer is formed.

According to a second aspect of the present invention, in the semiconductor structure of the first aspect, the high melting point material is a semiconductor material that does not thermally decompose at the growth temperature of the gallium nitride-based compound semiconductor. And

According to a third aspect of the present invention, in the semiconductor structure according to the second aspect, the high melting point material is a gallium nitride-based compound semiconductor having a melting point of 900 ° C. or more under a growth pressure. .

According to a fourth aspect of the present invention, there is provided a semiconductor structure.
The semiconductor structure of 2 or 3, wherein the first semiconductor layer _{B 1-xyz Al x Ga y} In z N (0 ≦ x ≦ 1,0 ≦
consists y ≦ 1,0 ≦ z ≦ 1) , the second semiconductor layer _{B 1-lmn Al l Ga m} In n N (0 ≦ l ≦ 1,0 ≦ m ≦
1, 0 ≦ n ≦ 1).

According to a fifth aspect of the present invention, there is provided a semiconductor device having the semiconductor structure according to any one of the first to fourth aspects.

According to a sixth aspect of the present invention, in the crystal growth method, a second semiconductor layer made of a high melting point material and a first semiconductor layer made of a gallium nitride-based compound semiconductor are sequentially grown on a silicon substrate. I have.

According to a seventh aspect of the present invention, there is provided a crystal growth method.
In the crystal growth method according to the above, on the silicon substrate,
_{B 1-lmn Al l Ga m} In n N (0 ≦ l ≦ 1,0 ≦ m ≦
1, 0 ≦ n ≦ 1 composition) are sequentially growing a plurality of different layers and the second semiconductor layer of the laminated structure, then B _1-xyz Al on the second semiconductor layer _x Ga _y In _z N (0 ≦ x ≦ 1, 0
≦ y ≦ 1, 0 ≦ z ≦ 1) to form a first semiconductor layer.

In the semiconductor structure according to the first aspect of the present invention,
By forming the second semiconductor layer made of a high melting point material between the silicon substrate and the first semiconductor layer, the surface of the silicon substrate is coated, and the reaction between the silicon substrate and the first semiconductor layer is performed. And the crystallinity and surface flatness of the first semiconductor layer are improved. Thereby, the first
The semiconductor layer has good surface flatness and crystallinity, and eliminates the possibility that foreign substances such as polycrystals precipitate on the surface. Further, when a semiconductor element is formed on the first semiconductor layer, the element has higher performance and higher reliability.

[0016] As the first semiconductor _{layer, B 1-xyz Al x Ga} y In z N (0 is a compound semiconductor of gallium nitride
≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1) are preferable. The first semiconductor layer preferably has a thickness of 2 μm or less. This is because if the thickness exceeds 2 μm, cracks easily occur in the semiconductor layer. As the second semiconductor layer, the melting point under a growth pressure is a compound semiconductor of 900 ° C. or more gallium nitride-based _{B 1-lmn Al l Ga m} In n N (0
≦ l ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1) It is preferable to adopt a laminated structure of a plurality of layers having different compositions.

[0017] _{B 1-lmn Al l Ga m} In n N (0 ≦ l ≦
The preferred range of the composition l of 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1) is 0.2 ≦ l ≦ 1. When l is smaller than 0.2, the effect of suppressing thermal decomposition is small. The B _1-lmn Al _l Ga _m
The preferred range of the thickness of the In _n N laminated structure is 200 n
m and 500 nm or less. If the thickness is less than 200 nm, the effect of suppressing thermal decomposition is small, and if it is more than 500 nm, cracks may occur.

In the semiconductor device according to the fifth aspect, the first aspect is as follows.
The gallium nitride-based compound semiconductor device has high performance and high reliability by providing the semiconductor structure according to any one of (4) to (4).

According to a sixth aspect of the present invention, a second semiconductor layer made of a high melting point material and a first semiconductor layer made of a gallium nitride-based compound semiconductor are sequentially grown on a silicon substrate. The second semiconductor layer coats the surface of the silicon substrate and improves the crystallinity and surface flatness of the growing first semiconductor layer by its own effect of suppressing thermal decomposition. This makes it possible to form the first semiconductor layer having good surface flatness and crystallinity on the silicon substrate.

Further, the second semiconductor layer becomes a semiconductor layer having a high melting point at a growth temperature of 900 ° C. or higher, so that it is not necessary to perform a heat treatment for crystallization. This eliminates the need for crystallization by heat treatment after deposition as in the conventional case, and as a result, the manufacturing process is shortened and the manufacturing cost is reduced. Further, the second semiconductor layer is a layer on the silicon substrate side B
_{1-lmn Al l Ga m In} n AlN was l = 1 in N, the A
The layer above the _{lN B 1-lm Al l Ga} m N (0.2 ≦ l ≦
If the two-layer structure of 1) is adopted, AlN in contact with the silicon substrate
Further enhances the effect of inhibiting thermal decomposition. The growth temperature of AlN is preferably set to 1100 ° C. or higher. When AlN is grown at a temperature of 1100 ° C. or higher, the AlN becomes a high-melting-point semiconductor layer, does not require heat treatment for crystallization, saves labor, and increases production efficiency.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a semiconductor structure, a semiconductor device having the same and a crystal growth method according to the present invention will be described with reference to the drawings. [First Embodiment] FIG. 1 shows a G according to a first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a semiconductor structure using an aN-based compound semiconductor, and a second semiconductor layer 2 containing a GaN-based compound semiconductor containing Al on a (111) plane of an n-Si substrate 1;
A first semiconductor layer 3 of a GaN-based compound semiconductor having a different composition from that of the semiconductor layer 2 containing Al is sequentially stacked.

The second semiconductor layer 2 is made of B _{1 -lmn} Al ₁ Ga
A laminated structure of a plurality of layers having different compositions of _m In _n N (0 ≦ l ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1), for example, the AlN layer 11 in contact with the Si substrate 1 and the AlN layer 11 Al formed
It is composed of two layers of _l Ga _1-l N layer 12. The second semiconductor layer 2 naturally becomes an n-type semiconductor because Si diffuses from the Si substrate 1, and therefore, the Si substrate 1
Then, it becomes possible to pass a current through the first semiconductor layer 3. The first semiconductor layer _{3, B 1-xyz Al x Ga} y In z N (0 ≦
x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1), for example, a GaN layer.

This semiconductor structure corresponds to (1) of the n-Si substrate 1.
11) surface, the AlN layer 11 is grown at 900 ° C. above the growth temperature, followed by, Al _l G at 900 ° C. or higher growth temperature
a _1-lN layer 12 is grown to form the second semiconductor layer 2 having a two-layer structure, and then 900 ° C. is formed on the Al ₁ Ga _1-lN layer 12.
It can be obtained by growing the first semiconductor layer 3 at the above growth temperature. If this semiconductor structure is applied to a semiconductor device, a gallium nitride-based compound semiconductor device with high performance and high reliability can be obtained.

Next, examples and comparative examples of the semiconductor structure will be described. Example 1 A film was formed by metal organic chemical vapor deposition (MOCVD). First, the cleaned plane orientation (1
11) The n-Si substrate 1 was set, and while the H ₂ (carrier gas) was flowing, the substrate temperature was set to 1150 ° C. to thermally clean the Si substrate 1. Next, the substrate temperature was set to 1100 ° C., trimethyl aluminum (TMA) and NH ₃ were supplied into the reaction furnace, and AlN was placed on the Si substrate 1.
Layer 11 (thickness: 80 nm) was grown.

Subsequently, the substrate temperature is set to 1080 ° C., trimethylgallium (TMG), TMA and NH ₃ are supplied, and an Al _0.25 Ga _0.75 N layer (film thickness: 2) is formed on the AlN layer 11.
50 nm), and the AlN layer 11 and Al _0.25 Ga
_{The 0.75} N layer was used as the second semiconductor layer 2. Subsequently, in order to grow the first semiconductor layer 3 on the second semiconductor layer 2, TMG and NH ₃ are supplied as reaction gases at a substrate temperature of 1080 ° C. to grow a GaN layer (thickness: 1 μm). Was.

The surface of the grown GaN layer ((0004)
Surface) was mirror-like, and no cracks or bits were observed. Further, the (00) of the GaN layer was
04) The full width at half-maximum (FWHM) of the rocking curve of the diffraction peak from the plane was measured (the smaller the FWHM, the better the crystallinity), and the FWHM of the rocking curve was 600 arcsec. Met.

Comparative Example 1 Metal-organic chemical vapor deposition (MOC)
VD method). The cleaned n-Si substrate 1 having a plane orientation of (111) was set in a reaction furnace, and the substrate temperature was set to 1150 ° C. while flowing H ₂ gas to perform thermal cleaning of the Si substrate 1. Next, the substrate temperature is set to 500
C., TMA and NH ₃ were supplied into the reaction furnace, and an AlN layer 11 (thickness: 30 nm) was deposited on the Si substrate 1. Subsequently, TM was used as a reaction gas at a substrate temperature of 1080 ° C.
G and NH ₃ were supplied to grow a GaN layer (film thickness: 1 μm) of the first semiconductor layer 3 on the AlN layer 11.

The surface of the GaN layer is dull gray,
Many cracks and bits, and partially polycrystalline GaN fine particles were observed. In addition, Ga is obtained by a double crystal X-ray diffraction method.
When the FWHM of the locking cav of the diffraction peak from the (0004) plane of the N layer was measured, it was found to be 2000 arc
sec, which clearly indicates that the crystallinity is lower than that in Example 1.

Comparative Example 2 Metal-organic chemical vapor deposition (MOC)
VD method). The cleaned n-Si substrate 1 having a plane orientation of (111) was set in a reaction furnace, and the substrate temperature was set to 1150 ° C. while flowing H ₂ to thermally clean the Si substrate 1. Next, the substrate temperature was set to 500 ° C., and TMG and NH ₃ were supplied into the reaction furnace.
A GaN layer (thickness: 30 nm) was deposited thereon. Subsequently, at a substrate temperature of 1080 ° C., TMG, NH
₃ is supplied to the first semiconductor layer 3 on the GaNN layer.
An aN layer (film thickness: 1 μm) was grown.

The surface of the GaN layer is matte black,
Many cracks and bits, and partially polycrystalline GaN fine particles were observed. In addition, Ga is obtained by a two-crystal X-ray diffraction method.
The FWHM of the rocking curve of the diffraction peak from the (0004) plane of the N layer was measured to be 3000 arc.
sec.

According to the semiconductor structure of this embodiment, nS
to i of the substrate 1 (111) _{plane, B 1- lmn Al l Ga m} I
forming a second semiconductor layer 2 having a multilayer structure of a plurality of layers having different compositions of n _n N (0 ≦ l ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1), and forming the second semiconductor layer 2 on the second semiconductor layer 2 B, which is the first semiconductor layer 3
_{1-xyz Al x Ga y In} z N (0 ≦ x ≦ 1,0 ≦ y ≦ 1,
0 ≦ z ≦ 1), the reaction between the n-Si substrate 1 and the first semiconductor layer 3 can be suppressed by coating the surface of the n-Si substrate 1, and the first semiconductor The crystallinity and surface flatness of the layer 3 can be improved.

Therefore, the surface flatness and crystallinity of the first semiconductor layer 3 are very excellent, and there is no possibility that foreign matter such as polycrystals is deposited on the surface of the first semiconductor layer 3. If a GaN-based compound semiconductor device is formed on the first semiconductor layer 3, the GaN-based compound semiconductor device can have higher performance and higher reliability.

According to the crystal growth method of this embodiment, n-
The Si substrate 1 (111) plane, an AlN layer 11 is grown, followed by growing the Al _z Ga _1-z N layer 12, Al _z
Since the GaN layer which is the first semiconductor layer 3 is grown on the Ga _1-z N layer 12, the AlN layer 11 and the Al _z Ga _1-z N layer 1
2 coats the surface of the n-Si substrate 1 and improves the crystallinity and surface flatness of the growing first semiconductor layer 3 by its own effect of suppressing thermal decomposition. Can be. Therefore, the first semiconductor layer 3 having excellent surface flatness and crystallinity is formed on the Si substrate 1.
Can be formed.

Further, since the second semiconductor layer 2 becomes a semiconductor layer having a high melting point at a growth temperature of 900 ° C. or higher, it is not necessary to perform a heat treatment for crystallization. Therefore, the manufacturing process can be shortened, and the manufacturing cost can be reduced.

[Second Embodiment] FIG. 2 is a sectional view showing a semiconductor structure using a GaN-based compound semiconductor according to a second embodiment of the present invention. , A second semiconductor layer 21 containing a GaN-based compound semiconductor containing Al, and a first semiconductor layer 3 of a GaN-based compound semiconductor containing Al having a different composition from that of the second semiconductor layer 21.

[0036] The second semiconductor layer 21, B _1-lmn Al _l G
_{a m In n N (0 ≦} l ≦ 1,0 ≦ m ≦ 1,0 ≦ n ≦ 1) laminated structure of different compositions plurality of layers of, for example, an AlN layer 11 in contact with the Si substrate 1, AlN layer 11 above A plurality of AlGaN layers having different compositions of Al ₁ Ga _1-l N sequentially laminated on
For example, Al _0.80 Ga _0.20 N layer 22, Al _0.60 Ga _{0. 40}
N layer 23, Al _0.40 Ga _0.60 N layer 24 and Al _0.25 Ga
It is composed of four layers of _0.75 N layers 25. Also in the second semiconductor layer 21, Si diffuses from the Si substrate 1 and naturally becomes an n-type semiconductor.
A current can flow through the substrate 1 and the first semiconductor layer 3.

This semiconductor structure corresponds to (1) of the n-Si substrate 1.
11) The AlN layer 11 is grown on the surface at a growth temperature of 900 ° C. or higher.
Growth, followed by Al at a growth temperature of 900 ° C. or higher._0.80
Ga _0.20N layer 22, Al_0.60Ga_0.40N layer 23, Al
_0.40Ga_0.60N layer 24, Al_{0. twenty five}Ga_0.75N layer 25
Next, the second semiconductor layer 21 is laminated, and then the second semiconductor layer 21 is formed.
2 at a growth temperature of 900 ° C. or higher.
It can be obtained by growing the semiconductor layer 3.

Next, an embodiment of this semiconductor structure will be described. Example 2 A film was formed by metal organic chemical vapor deposition (MOCVD). First, the cleaned plane orientation (1
11) The n-Si substrate 1 was set, and while the H ₂ (carrier gas) was flowing, the substrate temperature was set to 1150 ° C. to thermally clean the Si substrate 1. Next, TMA and NH ₃ were supplied into the reaction furnace at a substrate temperature of 1100 ° C., and an AlN layer 11 (thickness: 80 nm) was grown on the Si substrate 1.

Subsequently, the substrate temperature was set to 1080 ° C., and TM
G, TMA and NH ₃ are supplied, and Al is formed on the AlN layer 11.
_0.80 Ga _0.20 N layer 22 (film thickness: 50 nm), Al _0.60 G
a _{0. 40} N layer 23 (thickness: 50nm), Al _0.40 Ga _0.60
N layer 24 (film thickness: 50 nm), Al _0.25 Ga _0.75 N layer 2
5 (film thickness: 100 nm) were sequentially laminated to form a second semiconductor layer 21. Subsequently, the substrate temperature was set to 1080 ° C., and TMG and NH ₃ were supplied as reaction gases to grow the first semiconductor layer 3 on the second semiconductor layer 21, and GaN was supplied.
A layer (thickness: 1 μm) was grown.

The surface of the grown GaN layer ((0004)
Surface) was mirror-like, and no cracks or bits were observed. Further, the (00) of the GaN layer was
When the half width (FWHM) of the rocking curve of the diffraction peak from the 04) plane was measured, the FWHM of the rocking curve was 700 arcsec.

In the semiconductor structure of the present embodiment, the same effects as those of the semiconductor structure of the first embodiment can be obtained. Moreover, the second semiconductor layer 21 is made of AlN
Layer 11, Al _0.80 Ga _0.20 N layer 22, Al _0.60 Ga _0.40
N layer 23, Al _0.40 Ga _0.60 N layer 24 and Al _0.25 Ga
The first semiconductor layer 3 has a five-layer structure of _0.75 N layers 25.
Can be further improved in crystallinity and surface flatness.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to the embodiments and changes in the design and the like may be made without departing from the gist of the present invention. It is possible. For example, in the semiconductor structure of the present embodiment, the film is formed by the MOCVD method.
In addition to MOCVD, for example, molecular beam epitaxy (M
(BE method), hydride vapor phase epitaxy (HVPE), sublimation, liquid phase epitaxy, or the like. Also,
Although H ₂ was used as the carrier gas, N ₂ may be used as needed.

In the second embodiment, the second semiconductor layer 21 has a five-layer structure of AlN layers 11 to Al _0.25 Ga _0.75 N layers 25. However, the second semiconductor layer 21 is formed of Al ₁ Ga _{1 -l}
Any structure may be used as long as it has a structure in which a plurality of AlGaN layers having different N compositions are stacked, and the composition and the number of stacked layers may be determined as necessary.

[0044]

As described above, according to the semiconductor structure of the first aspect of the present invention, a second semiconductor layer made of a high melting point material is formed between a silicon substrate and a first semiconductor layer. Therefore, by coating the surface of the silicon substrate, the reaction between the silicon substrate and the first semiconductor layer can be suppressed, and the crystallinity and surface flatness of the first semiconductor layer can be improved. . Therefore, the surface flatness and crystallinity of the first semiconductor layer are good, and there is no possibility that foreign substances such as polycrystals are deposited on the surface.

According to a fifth aspect of the present invention, since the semiconductor device according to any one of the first to fourth aspects is provided, the performance of the gallium nitride-based compound semiconductor device on the silicon substrate can be improved. Reliability can be improved.

According to the crystal growth method of the sixth aspect, the second semiconductor layer made of a high melting point material is formed on the silicon substrate.
Since the first semiconductor layer made of a gallium nitride-based compound semiconductor is sequentially grown, the second semiconductor layer coats the surface of the silicon substrate, and the first semiconductor layer grows due to its own thermal decomposition suppressing effect. Crystallinity and surface flatness can be improved. Therefore, a first semiconductor layer having excellent surface flatness and crystallinity can be formed over a silicon substrate.

Further, since the second semiconductor layer becomes a semiconductor layer having a high melting point at a growth temperature of 900 ° C. or more, it is not necessary to perform a heat treatment for crystallization. As a result, there is no need to perform crystallization by heat treatment after deposition as in the conventional case, and the manufacturing process can be shortened, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a semiconductor structure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a semiconductor structure according to a second embodiment of the present invention.

[Explanation of symbols]

1 n-Si substrate 2 second semiconductor layer 3 first semiconductor layer 11 AlN layer 12 Al _l Ga _1-l N layer 21 and the second semiconductor layer 22 Al _0.80 Ga _0.20 N layer 23 Al _0.60 Ga _0.40 N layer 24 Al _0.40 Ga _0.60 N layer 25 Al _0.25 Ga _0.75 N layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Egawa Nagoya Institute of Technology, Okisho-cho, Showa-ku, Nagoya-shi, Aichi (72) Inventor Masayoshi Umeno Nagoya Institute of Technology, Oki-sho-cho, Showa-ku, Nagoya, Aichi (72) Inventor Nakao Akutsu 1-16-7 Nishi-Shimbashi, Minato-ku, Tokyo Nippon Oxide Co., Ltd. (72) Inventor Isao Matsumoto 1-16-7 Nishi-Shimbashi, Minato-ku, Tokyo F-term in Nippon Oxide Co., Ltd. (Reference) 4K030 AA11 AA13 BA02 BA08 BA11 BA26 BA38 BB13 CA04 DA03 HA01 JA06 JA10 LA14 5F041 AA40 CA33 CA34 CA40 CA65 5F045 AA04 AB14 AB17 AB19 AC08 AC12 AC15 AD14 AF03 BB01 BB04 BB12 BB16 DA53 DA57 HA02 5KA05

Claims (7)

[Claims] 1. A semiconductor structure in which a first semiconductor layer made of a gallium nitride-based compound semiconductor is formed on a silicon substrate, wherein a high melting point material is interposed between the silicon substrate and the first semiconductor layer. A semiconductor structure comprising a second semiconductor layer made of: 2. The semiconductor structure according to claim 1, wherein said high melting point material is a semiconductor material which does not undergo thermal decomposition at a growth temperature of said gallium nitride based compound semiconductor. 3. The semiconductor structure according to claim 2, wherein the high melting point material is a gallium nitride-based compound semiconductor having a melting point of 900 ° C. or more under a growth pressure. 4. The method according to claim 1, wherein the first semiconductor layer is B _1-xyz Al _x G
_{a y In z N (0 ≦} x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1) consists, said second semiconductor layer _{B 1-lmn Al l Ga m} I
4. The semiconductor structure according to claim 1, wherein the semiconductor structure comprises a stacked structure of a plurality of layers having different compositions of n _n N (0 ≦ l ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 1). 5. A semiconductor device comprising the semiconductor structure according to claim 1. Description: 6. A crystal growth method comprising sequentially growing a second semiconductor layer made of a high melting point material and a first semiconductor layer made of a gallium nitride-based compound semiconductor on a silicon substrate. To wherein said silicon substrate, B _1-lmn Al _{l
Ga m In n N (0 ≦} l ≦ 1,0 ≦ m ≦ 1,0 ≦ n ≦ 1)
Are sequentially grown to form a second layer of the laminated structure.
And then B on the second semiconductor layer
_{1-xyz Al x Ga y In} z N (0 ≦ x ≦ 1,0 ≦ y ≦ 1,
7. The crystal growth method according to claim 6, wherein 0 ≦ z ≦ 1) is grown to form a first semiconductor layer.