JP2003037288A - Semiconductor crystal film growth method - Google Patents

Abstract

(57) [Problem] To provide a pn junction type LED similar to the conventional one,
A method of growing a semiconductor crystal film capable of improving its crystal structure, increasing the growth rate, reducing lattice defects, and improving the quality. SOLUTION: In a method for growing a semiconductor crystal film in which a GaN layer is grown on a sapphire substrate via a buffer layer, and then an InGaN layer or an InN layer is grown thereon, the GaN layer is grown at about 820 ° C. or less. Performed at about 500 ° C. or more, and grown the InGaN layer or InN layer at about 800 ° C.
This is done below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor crystal film growth method for growing a semiconductor crystal film on a substrate.

[0002]

2. Description of the Related Art FIG. 4 shows a pn having an asymmetric double hetero structure.
It is a section construction drawing of a junction type blue LED. As shown in this figure, a GaN layer is grown on the surface of a sapphire substrate via an AlN buffer layer, and a semiconductor film of InGaN is further grown thereon to form a blue LED that emits blue (B). You can Further, in this figure, three primary colors of red (R), green (G), and blue (B) can be emitted by changing the component ratio of InN in InGaN, among which green (G) and blue ( The two primary color LEDs of B) have already been realized. That is, in general, InGa
N is a double heterostructure with GaN or InGaN /
Lasers and light-emitting diode devices are manufactured with the multi-quantum well structure of GaN.

FIG. 5 is a diagram showing the relationship between the band gap and the lattice constant of main semiconductors. In this figure, the band gap (eV) corresponds to the wavelength (μm), and red (R),
The wavelength becomes shorter in the order of green (G) and blue (B), and InG
The component ratio of InN in aN becomes low. That is, in comparison with the already realized LEDs of the two primary colors of green (G) and blue (B), in the red LED which emits red (R) having a wavelength of about 650 μm, the molar fraction of InN in InGaN is To about 0.
It needs to be increased to 7 or higher.

FIG. 6 is a diagram showing the relationship between the molar fraction y of InN in InGaN and the equilibrium temperature. As shown in this figure,
When the molar fraction y of InN in InGaN is increased to about 0.7 or more to form a red LED emitting red (R) having a wavelength of about 650 μm, the equilibrium temperature becomes about 500 ° C. or lower. Therefore, in the process of growing the InGaN semiconductor film on the surface of the GaN layer, the GaN layer and the formed I
There is a problem that InGaN is thermally decomposed when nGaN is heated to about 500 ° C. or higher. Note that FIG. 6 shows the relationship in the case of heating in a vacuum in which the raw material partial pressure is low, and this case is not followed in the case of vapor phase growth. For example, in Nichia, InGa of about 0.2 at about 750 ° C to about 800 ° C
Growing N.

As a means for growing an InGaN semiconductor film on the surface of a sapphire substrate, a "semiconductor crystal film growth method" is disclosed (Japanese Patent Laid-Open No. 04-164895).
issue). This method uses an apparatus schematically shown in FIG.
A semiconductor film is grown on the upper surface of the substrate 1 by the OVPE method (organic metal compound vapor deposition method). That is, in this method, the sapphire substrate 1 is placed on the susceptor 4, the inside of the reaction vessel 6 is replaced with H ₂ , and the temperature of the substrate 1 is set to about 5 ° C.
The temperature is maintained at 50 ° C., hydrogen and nitrogen are supplied from the auxiliary injection pipe 3, and ammonia gas, hydrogen, TMG (trimethylgallium) gas and TMI (trimethylindium) are supplied from the reaction gas injection pipe 2.
By supplying gas, InGaN is formed on the surface of the sapphire substrate 1.
To grow the semiconductor film of. In this figure, 5 is a shaft, 7 is a heater, 8 is an exhaust port, and 9 is a radiation thermometer. Further, instead of MOVPE (organic metal compound vapor phase epitaxy), MOMBE method (organic metal molecule beam epitaxy method) can be applied.

By this method, a Ga _0.94 In _0.06 N semiconductor film has been successfully grown to a uniform thickness of 2 μm over the entire surface of a 2-inch substrate. However, according to this method, the molar fraction y of InN in the grown InGaN is y.
Has a low value (0.06), and a red LED that emits red (R) cannot be formed. That is, although ammonia is used as the precursor of nitrogen in this example,
Since ammonia has a large N—H bond energy, it is necessary to raise the substrate temperature as much as possible in order to cause the reaction on the substrate. However, InGaN that emits red light
Has a high composition of InN, and as described above, when the mole fraction y of InN is high, the decomposition temperature is lowered to about 500 ° C. Therefore, in this method, the substrate temperature is too high,
Red-emitting InGaN could not be grown.
However, for example, in Nichia and others, 0.2-0.3
InGaN of In composition is growing.

FIG. 8 shows the MO of GaN using a low temperature deposited layer.
It is the schematic of the substrate temperature program of VPE (organic metal compound vapor phase epitaxy). As shown in this figure, conventionally, a buffer layer of AlN (or GaN) is formed on a sapphire substrate at about 500 ° C., and then GaN is formed at about 1100 ° C. Further, the InGaN layer thereabove is grown at about 750 ° C. in the above example.

FIG. 9 shows the outline of the substrate temperature dependence of the growth rate of the binary compounds InN, GaM, and AlN when it is assumed that ammonia is overgrown with respect to the group III raw material. . There is a temperature region where the growth rate is constant, and the growth rate decreases at higher and lower temperatures. The growth rate decreases at low temperatures because the decomposition efficiency of the raw material gas decreases. Further, the growth rate decreases at high temperature because sublimation increases. At high temperature, the etching reaction of hydrogen becomes significant, so that the decrease in the growth rate occurs at a lower temperature.

[0009]

As described above, in the conventional pn junction type LED, a GaN layer is grown on a sapphire substrate through a buffer layer at about 1000 ° C., and then an InGaN layer is grown thereon. It was grown at about 750 ° C. However, the LED structure by this method is InGaN
There is a problem that the crystal growth rate of the layer is slow, lattice defects are likely to occur, and the quality is low.

The present invention was created to solve such problems. That is, an object of the present invention is to provide a semiconductor crystal film growth method capable of improving the crystal structure, increasing the growth rate, reducing lattice defects and improving the quality of the pn junction type LED similar to the conventional one. To provide.

[0011]

In order to solve the above problems, the inventors of the present invention focused on the lattice polarity of GaN having a wurtzite structure, and the effect of temperature on its decomposition rate and growth rate. I studied hard. As a result, about 1000
The growth polarity of the GaN layer at ℃ is (0001) plane (G
The (a-pole) is dominant, and the growth of the InGaN layer thereon is also the (0001) plane having the same polarity. On the other hand, about 820
In the growth at a low temperature of ℃ or less, the growth of this (0001) plane is slower than the growth of the opposite (000-1) plane (N pole) and the decomposition rate is faster, so that lattice defects occur. It was found that the quality is easy and the quality is deteriorated.
The present invention is based on this novel finding.

That is, according to the present invention, a GaN layer is grown on a sapphire substrate via a buffer layer, and then an InGaN layer or an InN layer is grown on the GaN layer. Growth about 8
There is provided a method for growing a semiconductor crystal film, which is performed at 20 ° C. or lower and about 500 ° C. or higher, and the InGaN layer or the InN layer is grown at about 800 ° C. or lower.

According to the method of the present invention, the GaN layer is formed at a temperature of about 820 ° C. or lower and about 500 ° C. or higher, which is lower than the conventional temperature.
In this temperature range, the growth polarity of the GaN layer is (000-
1) The surface (N pole) becomes dominant. Next, since the InGaN layer or the InN layer on the GaN layer is performed at about 800 ° C. or lower, the molar fraction y of InN can be increased (for example, about 0.7 or more) to prevent thermal decomposition of InGaN. In addition, in this InGaN layer or InN layer, the GaN layer as the base of the InGaN layer or InN layer grows on the (000-1) plane.
The growth polarity of the GaN layer or the InN layer is the same as that of the underlayer (0
It becomes the 0-1) plane.

Further, in the low temperature region of about 800 ° C. or lower and about 400 ° C. or higher, the InGaN layer or the InN layer (000-
From the results of the above research, the growth of 1) plane is
The growth rate is faster and the decomposition rate is slower than the growth of the (01) plane, and further because the crystal atom arrangement is less likely to shift due to the energetically stable growth direction, a high-quality InGaN layer or InN layer can be obtained. It was confirmed that it was obtained. Therefore, In having a growth polarity of (000-1) plane
Since the GaN layer or the InN layer has a reduced lattice defect as compared with the case of growing the (0001) plane, the quality thereof is superior to the conventional one.

According to a preferred embodiment of the present invention, the growth of each layer is performed by MOVPE (organic metal compound vapor phase epitaxy), HVPE (hydride vapor phase epitaxy) or MOM.
According to the BE method (organic metal molecular beam epitaxy method).
By these growth methods, each layer can be efficiently grown while setting the substrate temperature at a predetermined temperature.

The Ga precursors are GaCl and Ga.
(CH ₃ ) ₃ or Ga (C ₂ H ₅ ) ₃ , the precursor of In is In (CH ₃ ) ₃ or In (C ₂ H ₅ ) ₃ , and the precursor of N is ammonia, MNH ₂ ( Methylamine), DMN
H (dimethylamine), TMN (trimethylamine),
It is N ₂ H ₂ (hydrazine), (CH ₃ ) NH—NH ₂ (monomethylhydrazine), or (CH ₃ ) ₂ N—NH ₂ (dimethylhydrazine). By exciting and decomposing these precursors, the GaN layer, the InGaN layer and the InN layer can be efficiently grown.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the common part is denoted by the same reference numeral, and the duplicated description will be omitted.

FIG. 1 is a schematic diagram of a wurtzite crystal structure (A) and a tetrahedral cluster (B). GaN, InGaN
Group III nitride crystals such as InN and In usually have a wurtzite type crystal structure or a zinc blend type structure. Here, the case of the wurtzite type crystal structure will be described. The wurtzite crystal structure does not have a center of symmetry and has a (0001) plane (Ga pole) and a (000-1) plane (N pole). As is apparent from FIG. 1, the structure in which the group III atom (Ga, In, etc.) and the group V atom (N) are exchanged has the original crystal orientation reversed. In these two directions, the atomic species appearing on the outermost surface and the bonding arrangement with the surrounding atoms are different, and therefore the surface reconstruction structure is different. Which polarity the group III nitride crystal grows in depends on the type of substrate and other growth conditions. Since the surface structure differs depending on the polarity, the crystal growth process also differs. As a result, a large difference appears in the microstructure and growth surface shape of the obtained epitaxial layer.

FIG. 2 shows GaN obtained in an example described later.
It is a relationship diagram of the decomposition rate of a layer and temperature. In this figure,
The horizontal axis is temperature (upper axis) and its reciprocal (lower axis), and the vertical axis is GaN.
Layer decomposition rate, ● in the figure is the (0001) plane (Ga pole),
◯ is the (000-1) plane (N pole). From this figure, at about 820 ° C., the decomposition rates of the (0001) plane and the (000-1) plane are reversed, and at the high temperature side, (000-1)
It can be seen that the decomposition rate of the (0001) plane is high on the low temperature side. It should be noted that the vertical axis in the figure is logarithmic display (exponential function display), and therefore the actual difference is two times or more.

FIG. 3 is a graph showing the relationship between the growth rate and the temperature of the GaN layer obtained in the examples described below. In this figure, the horizontal axis represents temperature, the vertical axis represents the growth rate of the GaN layer, ● in the figure represents the (0001) plane (Ga pole), and ○ represents the (000-1) plane (N pole). From this figure, at a growth rate of about 820 ° C., the (0001) plane and the (000-1) plane are reversed, and the growth rate of the (0001) plane is high on the high temperature side.
It can be seen that the growth rate of the (000-1) plane is high on the low temperature side.

From FIG. 2 and FIG. 3, at about 820 ° C. as a boundary,
In the lower temperature range up to about 750 ° C, (0
It can be seen that the growth rate of the (001) plane is low and its decomposition rate is high. That is, in this temperature region, the Ga electrode is violently etched, and the growth rate is slow, and as a result, it is considered that a poor quality GaN layer grows. Even in the growth of InN and InGaN, since InN and InGaN are III-V group compound semiconductors having the same crystal structure as GaN,
Similar to the growth of aN, it is assumed that there is a stable surface boundary around about 820 ° C. However, in the case of InGaN and InN, the decomposition vapor pressure is high at a high temperature of about 820 ° C. or higher, and growth cannot be performed under normal MOVPE and MOMBE growth conditions. Therefore, the original stable growth direction of InGaN and InN is the (000-1) direction, and the growth direction of InGaN and InN that is usually performed at present (000) is
1) is not a stable growth direction.

Based on the above-mentioned novel knowledge, in the method of the present invention, the temperature at which the GaN layer is grown on the sapphire substrate shown in FIG.
The temperature is drastically lowered from ℃, and the growth is performed at about 800 ℃ or less. As a result, from FIG. 2 and FIG. 3, in this temperature range,
The growth polarity of the GaN layer is dominated by the (000-1) plane. Further, in the present invention, the growth of the InGaN layer thereon is performed at about 500 ° C. or lower and about 400 ° C. or higher. Thereby, the growth polarity of the InGaN layer also becomes the same (000-1) plane.

That is, the GaN layer has a temperature of about 8
The GaN layer (00
0-1) plane and then InG on the GaN layer
The aN layer or the InN layer is formed at about 800 ° C. or lower. As a result, when the InGaN layer or InN layer is grown, the underlying GaN layer is formed on the (000-1) plane, so the growth polarity of the InGaN layer or InN layer is the same as that of the underlying layer (000). -1) It becomes the surface. Further, in the temperature range of about 800 ° C. or lower, the growth rate of the (000-1) plane is higher than that of the conventional (0001) plane, and the decomposition rate is slower. Becomes

In the method of the present invention, the growth of each layer is
By VPE (hydride vapor phase epitaxy), MOVPE (organic metal compound vapor phase epitaxy), or MOMBE (metalorganic molecular beam epitaxy). That is, for example,
The sapphire substrate is adjusted in the reaction vessel by a temperature adjusting means (for example, a heater), and the GaN layer is grown at about 820 ° C. or lower and about 500 ° C. or higher. Further, the InGaN layer and the InN layer are formed at a temperature (for example, about 800 ° C. or lower) at which InGaN is not thermally decomposed.

Further, precursors of In, Ga and N are sequentially or simultaneously supplied from the gas introduction section into the reaction vessel. The precursor of Ga is GaCl, the precursor of N is ammonia, MN
H ₂ (methylamine), DMNH (dimethylamine),
TMN (trimethylamine), N ₂ H ₂ (hydrazine),
It may be (CH ₃ ) NH-NH ₂ (monomethylhydrazine) or (CH ₃ ) ₂ N-NH ₂ (dimethylhydrazine).

[0026]

EXAMPLES Examples of the present invention will be described below. GaN having a wurtzite structure has a polarity along the c-axis direction, that is, a (0001) plane (Ga pole) and a (000-1) plane (N
Poles). Therefore, it is very important to study the decomposition mechanism of GaN on the cleaning or etching surface. In this embodiment, a sapphire substrate (0001) is formed by using an in-situ gravity measurement monitor method (GM method).
The decomposition rate of the GaN single crystal on the plane with respect to the plane polarity was tested.

The test device comprises a vertical reaction tube and a micro weight recording device. This micro weight recorder is 0.004μ
g (3.3 × 10 ⁻⁶ μm of GaN with an area of 2.0 cm ²
Has almost the same sensitivity as Carrier gas is H ₂
And inert gas were used, and He was used as the inert gas. The hydrogen partial pressure (P _H2 ) in the carrier gas changes depending on the change in the ratio of H2 to H ₂ + He. One side of mirror-finished GaN substrate (0001) has a thickness of 1000Å
Covered with a layer of O ₂ and suspended from microbalance with silica fibers. Thereby, the polarity dependence of the GaN substrate (0001) surface can be measured.

FIG. 2 is a graph showing the relationship between the decomposition rate and the temperature of the GaN layer obtained in this test. As is clear from this figure, the decomposition rate in the H ₂ carrier gas environment (P _H2 = 1) increases exponentially with increasing temperature in the temperature range of 650 ° C. to 950 ° C. regardless of the plane polarity. . It was also revealed that the decomposition rate itself differs depending on the lattice polarity. In the low temperature range of 820 ° C or lower, the decomposition rate of the (0001) plane of GaN is (000-
1) faster than face. On the contrary, in the high temperature range from 850 ° C. to 950 ° C., the decomposition rate of the (000-1) plane of GaN is faster than that of the (0001) plane. The reason for this result is GaN
This is due to the difference in activation energy in the decomposition process of the (0001) plane and the (000-1) plane.

Further, GaN planes (0001) and (00
The relationship between the decomposition rate of the 0-1) plane and the hydrogen partial pressure was examined from 600 ° C to 950 ° C. As a result, it was clarified that in the low temperature region of 850 ° C. or lower, the decomposition rate of GaN is proportional to the 3/2 power of the hydrogen partial pressure regardless of the plane polarity. On the other hand, 85
In the high temperature region of 0 ° C. or higher, it was revealed that the decomposition rate is proportional to the 1/2 partial power of hydrogen partial pressure regardless of the polarity. This means that the rate-determining reaction that controls the decomposition rate differs between the low temperature region and the high temperature region. on the other hand,
From the thermodynamic analysis of the reaction between GaN (s) and H ₂ (g),
The main gas-phase molecular species generated in this reaction are NH ₃ and GaH.
It is clear that the rate-determining reaction by the reaction between hydrogen in the low temperature region and the hydrogen in the high temperature region is represented by the formula (1) and the formula (2), respectively. GaN (surface) + 3 / 2H ₂ (g) → Ga (surface) + NH ₃ (g) (1) (low temperature region) GaN (surface) + 1 / 2H ₂ (g) → N (surface) + GaH (g ) ・ ・ ・ (2) (High temperature area)

On the other hand, hydrogen gas is used as a carrier gas even during the growth of GaN.
Since hydrogen is generated by the growth reaction of N, GaN
It is necessary to consider that the reaction between the surface and hydrogen is occurring at the same time. Furthermore, the growth rate actually obtained is considered to be the difference between the precipitation reaction and the decomposition reaction. This is also clear from the relationship between growth and temperature in FIG.

From the above results, it is clear that, in decomposition and growth, the GaN (000-1) plane becomes dominant in the low temperature region and the GaN (0001) plane becomes dominant in the high temperature region.

According to the invention as described above, the following facts were clarified, and the growth conditions for obtaining high-quality InGaN and InN crystals were clarified.

Fact 1: In the growth using a nonpolar substrate crystal such as sapphire, the growth plane orientation of GaN grown on sapphire is determined by the growth temperature. The relationship between the temperature and the growth plane orientation is as follows:
In the high temperature region, it is the (0001) plane. Generally GaN is 1
A high temperature region near 000 ° C is used, and (000
1) Face growth is expected to become dominant, and in fact (0
It has been clarified that the 001) Ga termination surface is the growth surface.

Fact 2: When a GaAs (111) crystal is used as the substrate crystal, the GaAs (111) A plane is GaN (0
The (001) plane and the GaAs (111) B plane are (Gan (0
The 0-1) plane is equivalent to the bonding state of the III, V, and V atoms. To this end, GaAs (111) A
When the plane is used, good GaN growth is possible by growth at 1000 ° C. or higher after the growth of the buffer layer at about 500 ° C., and this is consistent with the fact that the surface is the (0001) plane. On the other hand, using the GaAs (111) B plane, about 50
In the growth at 850 ° C. or higher after the growth of the buffer layer at 0 ° C., good GaN growth is not obtained, and the growth surface of 1 μm or more is (0001), and the growth direction is early in the growth. It is clear that it is reversed.

(Note 1) The growth on the GaAs (111) A plane was carried out according to Y. Kumagai et al. Jpn. J.
Appl. Phys. 39 (2000) L149 and Y. Kumagai et al. Jpn. J. A
ppl. Phys. , 39 (2000) L703. Is clear from

(Note 2) The measurement of the growth plane is clear from the following presentation using our sample. 200
Spring 1st Annual Joint Lecture on Applied Physics 29a-L-2 Ogawa et al. (Group of Professor Akimoto, Faculty of Engineering, Nagoya University) (Content: GaAs (111) A and GaAs (11)
1) In GaN growth on the B-plane, the surface of the GaN buffer layer of 100 nm or less is the (0001) and (000-1) planes, respectively, and 920 to 100
Both surfaces were (0001) planes after growth of GaN of 1 micron or more at 0 ° C. )

Fact 3: The surface obtained by the growth experiment using the single crystal GaN substrate shown in FIG.
GaN is on the 1) plane and GaN (000-1) plane, respectively.
The (0001) plane and the GaN (000-1) plane were obtained regardless of the grown film thickness.

Fact 4: Conventional InGaN and InN have a buffer layer grown at about 500 ° C. on a sapphire substrate crystal, and then a GaN crystal grown at about 1000 ° C.
It is grown in a low temperature region of 00 ° C. or lower. For this reason, InGaN or InN having a stable (000-1) growth surface is grown on the (0001) growth surface, which induces defects due to instability of atomic arrangement and defects thereof. The resulting compositional separation occurs. For this reason, it is difficult to grow a high-quality crystal, and in particular, for InGaN or InN having a large In composition, a crystal having optical characteristics has not been obtained.

Fact 5: In for the purpose of laser device
In the growth of GaN or InN, G produced by thick film growth using a GaN single crystal substrate, a sapphire substrate, a GaAs substrate or the like prepared by a high pressure method or a sublimation method.
An aN single crystal substrate is used. In this case as well, since GaN and AIN are initially grown at about 1000 ° C., the GaN (0001) plane is used as the growth plane, and the same phenomenon as the above-mentioned fact 4 occurs.

Example 1 (1) In MOVPE growth using a sapphire substrate, a buffer layer was grown at about 500 ° C., then about 2 μm GaN was grown at 1000 ° C., and then 0.5 μm I at 780 ° C.
n0.2Ga0.8N was grown. On the other hand, in the same manner as (2), MOVPE growth was performed using a sapphire substrate, after the buffer layer was grown at about 500 ° C., about 2 μm GaN was grown at 800 ° C., and 0.5 μm In at 780 ° C.
The growth was 0.2 Ga 0.8 N. By surface analysis of the growth surface, the surface obtained in (1) is the (0001) plane,
(2) was the (000-1) plane. As a result of PL (photoluminescence) measurement at room temperature, the full width at half maximum of the sample grown at high temperature was 165 meV, whereas the low temperature G was measured.
The aN grown sample halved to 77 meV and the crystal quality was improved.

Example 2 Using the GaAs (111) B plane as a substrate crystal, a buffer layer was grown by MOVPE growth at about 500 ° C., and then GaN was grown at 1.5 μm at 780 ° C. and 780 thereon. 0.6 micron In at ℃
The growth was _0.3 Ga _0.7 N. Growth surface is (000-1)
It was confirmed that the surface. Further, in the grown InGaN mixed crystal, I which is often observed in the case of (0001) growth plane
It was clarified that clusters having a large n composition were not observed and a uniform mixed crystal was obtained.

Example 3: GaAs (111) B plane as substrate
It is used for crystallization, and the buffer layer is grown by MOVPE.
After growing at 500 ℃, GaN at 1.5 ℃ at 780 ℃
Grown on top of 0.2 micron In at 650 ° C.
_0.6Ga_0.4The growth of N. Growth surface is (000-1)
It was confirmed to be a face. Also, grown InGaN
The mixed crystal does not show phase separation, and a uniform mixed crystal can be obtained.
It was revealed. As a result of X-ray diffraction, about 2.1 min half
IN of price range_0.6Ga_0.4It was found that N was obtained. one
, Sapphire substrate or GaAs (111) A-plane substrate
Buffer layer at about 500 ° C by MOVPE growth using
After the growth, GaN is grown at about 950 ° C. and then In is grown at 650 ° C.
_0.6Ga_0.4We tried to grow N, but caused phase separation
No InGaN mixed crystal was obtained.

Example 4: GaN single crystal substrate (000-
Using the 1) plane as a substrate, GaN was grown to 2 μm at 750 ° C., and then an In _0.2 Ga _0.8 N mixed crystal was grown to 0.15 μm. A uniform composition was obtained without instability of the composition in the InGaN mixed crystal. On the other hand, in the growth based on the GaN (0001) plane, it was revealed that clusters having a large In composition existed in the mixed crystal. In addition, it was found by photoluminescence measurement that the FWHM of GaN (000-1) plane growth was small and the quality was good.

Example 5: GaN (000-1) plane was used as a substrate crystal and GaN was grown at 780 ° C. by MOVPE growth.
, 1.5 micron, and 0.2 at 650 ° C.
Micron InGaN was grown. Growth surface (000
It was confirmed that it was a (-1) plane. Also, grown In
No phase separation was observed in the GaN mixed crystal, which revealed that a uniform mixed crystal was obtained. It was confirmed by X-ray diffraction and photoluminescence.

According to the above-described method of the present invention, the GaN layer is formed at a temperature lower than that of the prior art at about 820 ° C. or lower and about 500 ° C. or higher. Therefore, in this temperature region, the growth polarity of the GaN layer is
The (000-1) plane (N pole) becomes dominant. Then G
The InGaN layer or InN layer on the aN layer has a temperature of about 800 ° C.
Since it is carried out below, the molar fraction y of InN can be increased (for example, about 0.7 or more) to prevent thermal decomposition of InGaN. Further, in this InGaN layer or InN layer, the underlying GaN layer grows on the (000-1) plane, so the growth polarity of the InGaN layer or InN layer is the same as that of the underlayer (000-1) plane. Becomes Furthermore, about 800 ℃ or less,
In the low temperature region of about 400 ° C. or higher, the InGaN layer or In
From the results of the above-mentioned research, it was confirmed that the growth rate of the (000-1) plane of the N layer was higher and the decomposition rate was slower than the conventional growth of the (0001) plane. Therefore, the InGaN layer or the InN layer whose growth polarity is the (000-1) plane has a lattice defect reduced as compared with the case of the growth of the (0001) plane, and therefore its quality is superior to the conventional one. Become.

The present invention is not limited to the above-described examples and embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0047]

As described above, according to the method for growing a semiconductor crystal film of the present invention, in a pn junction type LED similar to the conventional one, the crystal structure is improved, the growth rate is increased, and lattice defects are reduced. It has an excellent effect that its quality can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a wurtzite crystal structure (A) and a tetrahedral cluster (B).

FIG. 2 is a graph showing the relationship between the decomposition rate of a GaN layer and temperature.

FIG. 3 is a graph showing the relationship between the growth rate of a GaN layer and temperature.

FIG. 4 is a sectional structural view of a blue LED using InGaN.

FIG. 5 is a relationship diagram of a band gap and a lattice constant of main semiconductors.

FIG. 6 is a diagram showing a relationship between a molar fraction y of InN in InGaN and an equilibrium temperature.

FIG. 7 is a schematic view of a conventional method for growing a semiconductor crystal film.

FIG. 8 is a schematic diagram of a MOVPE (metal organic chemical vapor deposition) substrate temperature program for GaN using a low temperature deposited layer.

FIG. 9 is a schematic diagram of substrate temperature dependence of growth rate of binary compounds InN, GaM, and AlN.

[Explanation of symbols]

1 sapphire substrate, 2 reaction gas injection tube, 3 auxiliary injection tube, 4 susceptor, 5 shaft, 6 reaction vessel, 7
Heater, 8 exhaust ports, 9 radiation thermometer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Norihito Kawaguchi             3-1-15-1 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center (72) Inventor Miyuki Masaki             3-1-15-1 Toyosu, Koto-ku, Tokyo Ishikawajima             Harima Heavy Industries Tokyo Engineering Co., Ltd.             In the center F term (reference) 4G077 AA03 BE11 DA05 DB05 DB08                       ED06 EF01 HA02 SC02 TB03                       TB05 TC06 TC13                 5F041 AA40 CA04 CA34 CA40 CA64                       CA65 CA66                 5F045 AA04 AA05 AB14 AB17 AC08                       AC09 AC12 AD09 AD10 AD11                       AD12 AF09 BB09 BB12 CA11                       DA53

Claims (3)

[Claims] 1. A method for growing a semiconductor crystal film comprising growing a GaN layer on a sapphire substrate via a buffer layer and then growing an InGaN layer or an InN layer thereon, wherein the growth of the GaN layer is about 820 ° C. or less. A method for growing a semiconductor crystal film, wherein the growth is performed at about 500 ° C. or higher, and the growth of the InGaN layer or the InN layer is performed at about 800 ° C. or lower. 2. The growth of each layer is carried out by MOVPE (organic metal compound vapor phase epitaxy), HVPE (hydride vapor phase epitaxy) or MOMBE (metalorganic molecular beam epitaxy). 1. The method for growing a semiconductor crystal film according to 1. 3. The Ga precursor is GaCl or Ga (C).
H₃)₃Or Ga (C ₂H_Five)₃And the precursor of In is I
n (CH₃)₃Or In (C₂H_Five)₃And the precursor of N
Is ammonia, MNH₂(Methylamine), DMNH
(Dimethylamine), TMN (trimethylamine), N
₂H₂(Hydrazine), (CH₃) NH-NH ₂(Monomechi
(Hydrazine), or (CH₃)₂N-NH₂(Dimethylhi
Drazin) according to claim 1.
Method for growing semiconductor crystal film.