JPH07230953A - Vapor growth method for 3b-5b group compound semiconductor - Google Patents

Abstract

PURPOSE:To provide the vapor growth method with which epitaxial crystal of 3b-5b group compound used for a high efficiency light emission device can be manufactured on inductrial basis using nitrogen raw material at least containing hydrogen. CONSTITUTION:In the epitaxial vapor growth method for a 3b-5b compound semiconductor containing nitrogen as a group 5b element, at least hydrogen is used as nitrogen raw material, and it is characterized that the moisture content of the hydrazine is 100 weight ppm or smaller in this 3b-5b compound semiconductor epitaxial vapor growth method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial vapor phase growth method for a 3b-5b group compound semiconductor containing nitrogen as a 5b group and using hydrazine as a nitrogen source.

[0002]

2. Description of the Related Art A 3b-5b group compound semiconductor containing nitrogen as a 5b group is useful as a material for a light emitting device in the visible ultraviolet region. In particular, the general formula In _x Ga _y Al _z N (provided that 0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1, x + y + z =
The gallium nitride-based compound semiconductor represented by 1) is useful as a material for a light emitting device in the visible ultraviolet region. In particular,
It is known that the metalorganic vapor phase decomposition method (hereinafter referred to as MOVPE method) enables very good quality epitaxial vapor phase growth. However, in the conventional vapor phase growth method using ammonia as a raw material of nitrogen of Group 5b, it is general to grow at a high temperature of 900 ° C. or higher mainly because the thermal decomposition property of ammonia is poor. However, a high-quality compound semiconductor could not be obtained unless the ammonia was supplied in a molar ratio of 1000 or more as compared with the group 3b raw material.

Further, in the above general formula, the compound semiconductor containing In is generally grown at 800 ° C. or lower because the evaporation temperature of In crystal from the crystal is relatively low. Since the thermal decomposition rate of ammonia is not sufficient at such a low temperature, a large amount of ammonia is required, which is a problem in terms of industrial productivity. On the other hand, it was proposed that hydrazine, which is much more thermally decomposable than ammonia, could be used to solve some problems. However, in the case of using hydrazine, no one having excellent crystal quality has been obtained so far.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to epitaxially deposit a 3b-5b group compound semiconductor having excellent crystal quality, which can be used for a highly efficient light emitting device in a vapor phase growth method containing at least hydrazine as a nitrogen source. It is an object of the present invention to provide a vapor phase growth method capable of industrially producing crystals.

[0005]

As a result of intensive studies to solve these problems, the present inventors have found that when a specific hydrazine is used, it can be used in a highly efficient light emitting device. The inventors have found that an epitaxial crystal of a compound semiconductor can be produced, and completed the present invention. That is, the present invention is the invention described below. (1) In the method for epitaxially growing a 3b-5b group compound semiconductor containing nitrogen as a 5b group, at least hydrazine is used as a nitrogen source, and the water content of the hydrazine is 100 ppm by weight or less.
Method for epitaxial vapor deposition of group 5b compound semiconductor. (2) 3b-5b Group compound semiconductor, In _x Ga _y Al
_z N (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x
+ Y + z = 1) The compound semiconductor represented by the formula (1), wherein the epitaxial vapor phase growth method for a 3b-5b group compound semiconductor is described.

Next, the present invention will be described in detail. The method for epitaxially vapor-depositing a 3b-5b group compound semiconductor according to the present invention includes a compound of the 3b group element in the Mendeleev's periodic table of elements and a compound of the 5b group element containing at least nitrogen (N). The present invention relates to a method for epitaxially vapor-depositing a group compound semiconductor. Here, as the compound of the 3b group element and the compound of the 5b group element containing at least nitrogen (N), a volatile compound is usually used. In particular,
Examples of the 3b group element include B, Al, Ga, and In,
Examples of the Group 5b element include P, As, and Sb in addition to N. In particular, the general formula In _x Ga _y Al _z N (provided that 0 ≦ x
The compound semiconductor represented by ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x + y + z = 1) is useful and preferable as a material for a light emitting device in the visible ultraviolet region. Furthermore, the present invention relates to an epitaxial vapor phase growth method using at least hydrazine as a nitrogen source.

The epitaxial vapor phase growth method for a 3b-5b group compound semiconductor of the present invention is characterized by using hydrazine having a water content of 100 ppm by weight or less. The water content is preferably 10 weight p
pm or less, more preferably 1 ppm by weight or less.
When hydrazine having a water content of more than 100 ppm by weight is used as a nitrogen source, the compound semiconductor obtained has a high impurity concentration, and the luminous efficiency of a light emitting device using the compound semiconductor is low, which is not preferable.

Hydrazine having a water content of 100 ppm by weight or less can be obtained by dehydrating commercially available hydrazine with calcium carbide or the like and then distilling it in a nitrogen atmosphere. The water content can be adjusted by adjusting the degree of dehydration and the degree of distillation according to the purpose. Other than hydrazine, for example, ammonia, tert-butylamine, or the like can be used in combination as the nitrogen source. When using hydrazine and a material other than hydrazine as the raw material of nitrogen, it is necessary to set the water content of the whole nitrogen raw material to 100 ppm by weight or less, but commercially available products such as ammonia having a sufficiently low water content. The high-purity product (for example, one having a water content of 1 ppm by weight or less) may be used.

The present invention will be described below by taking the MOVPE method as an example.
Although described in detail, the present invention is not limited to this. The raw material of the Group 3b element used in the present invention is usually a general formula R ₁ R ₂ R ₃ B such as trimethylboron [(CH ₃ ) ₃ B) or triethylboron ((C ₂ H ₅ ) ₃ B).
(R ₁ , R ₂ and R ₃ are hydrogen or an alkyl group,
_At least one of ₁ , R ₂ and R ₃ is an alkyl group. ) Alkylboron represented by); trimethylgallium [Ga (CH ₃ ) ₃ , hereinafter sometimes referred to as TMG. ], Triethylgallium [Ga (C ₂ H ₅ ) ₃ , hereinafter sometimes referred to as TEG. ] Trialkylgallium; trimethylaluminum [Al (CH ₃ ) ₃ ; hereinafter sometimes referred to as TMA. ], Triethylaluminum [Al (C ₂ H ₅ ) ₃ , hereinafter sometimes referred to as TEA. ], Triisobutylaluminum [Al (i-C ₄
H _{9) 3]} trialkylaluminum such as trimethylamine alane [AlH ₃ N (CH _{3) 3];} trimethylindium [In (CH _{3) 3,} sometimes hereinafter referred to as TMI. ], Triethylindium [In (C ₂ H ₅ )]
₃ , hereinafter sometimes referred to as TEI. ] And the like trialkylindium and the like. These may be used alone or as a mixture. As these raw materials, commercially available high purity products can be used.

Next, as the raw material of the 5b group element,
Besides hydrazine, phosphine (PH₃); Tasha
Ributylphosphine [(CH₃)₃CPH₂〕,bird
Methyl phosphorus [(CH₃)₃P], triethyl phosphorus [(C
₂H_Five)₃P] and other general formulas R ₁R₂R₃P (R₁,
R₂, R₃Is hydrogen or an alkyl group, R₁,
R₂, R₃At least one of is an alkyl group. )so
Alkyl phosphorus represented; arsine (AsH₃); Tashi
Polybutylarsine [(CH₃)₃CAsH₂], Echi
Luarsin (C₂H_FiveAsH₂), Diethyl arsine
[(C₂H_Five)₂AsH], trimethylarsenic [(C
H₃)₃General formula R such as As]₁R₂R₃As (R₁, R
₂, R₃Is hydrogen or an alkyl group, R₁, R₂,
R₃At least one of is an alkyl group. )
Alkyl arsine; trimethyl antimony [(C
H₃)₃Sb], triethylantimony [(C₂H_Five)
₃Sb] and other general formulas R ₁R₂R₃Sb (R₁, R₂, R
₃Is hydrogen or an alkyl group, R₁, R₂, R₃of
At least one is an alkyl group. ) Al
Kilantimony is mixed with hydrazine and the
A compound semiconductor containing a Group V element can be obtained. this
It is preferable to use high-purity commercial products
Yes.

FIG. 1 is a MOVPE for implementing the present invention.
FIG. 3 is a schematic view of a vapor phase growth apparatus for a gallium nitride based compound semiconductor by the method. Hereinafter, the present invention will be specifically described with reference to FIG. As the carrier gas, hydrogen, nitrogen, a mixed gas thereof, or the like is used. The carrier gas whose flow rate is controlled by the mass flow controller 1 is sent to the bubbler 3 whose temperature is adjusted by the constant temperature bath 2, bubbled in the TMG contained in the bubbler, and introduced into the reactor 7 together with the evaporated TMG vapor. The amount of TMG introduced at this time is controlled by the vapor pressure determined by the liquid temperature and the flow rate of the carrier gas bubbled. On the other hand, hydrazine is also introduced into the reactor 7 by bubbling similarly to TMG. A graphite support (susceptor) 9 capable of high-frequency induction heating by an external coil 8 is installed in the reactor, and the mixed gas of the raw material and carrier gas is thermally decomposed near the substrate 10 installed thereon. An epitaxial crystal of gallium nitride based semiconductor grows on the substrate. The gas after the reaction is discharged from the exhaust hole 11.

Although the above is an example of the growth of gallium nitride,
TMA and / or TM using a gas supply device similar to that used for TMG with or instead of TMG
By supplying I, and by supplying phosphine, arsine, etc. together with hydrazine, nitrogen containing 3
An epitaxial crystal of a b-5b group compound semiconductor can be obtained.

[0013]

EXAMPLES The present invention will be described in detail below with reference to examples, but these are merely examples and do not limit the present invention in any way. Example 1 When a commercially available hydrazine was analyzed for impurities by gas chromatography, it contained 0.9% by weight of water. When this was dehydrated with calcium carbide and then distilled in a nitrogen atmosphere, it was confirmed that the water content was 100 ppm by weight.

Using this as a raw material, gallium nitride was grown by the apparatus shown in FIG. Supply amount of TMG 4.
1100 at 5 × 10 ^-5 mol / min, hydrazine supply rate of 1 × 10 ^-3 mol / min and carrier hydrogen gas of 4 liter / min.
As a result of growth at 30 ° C. for 30 minutes, a polycrystalline film of gallium nitride having an average film thickness of 4 μm was obtained. From the surface microscopic observation, it was confirmed that the crystals were aggregates of hexagonal crystallites. The electrical properties of this crystal were measured by the four-terminal method. As a result, the compound semiconductor was n-type, had an electron concentration of 4 × 10 ¹⁹ / cm ³ and an electron mobility of 2 at room temperature.
It was 0 cm ² / Vsec. The light-emitting device manufactured using the compound semiconductor exhibits significantly higher luminous efficiency than the light-emitting device manufactured using the compound semiconductor obtained in Comparative Example 1.

Comparative Example 1 Gallium nitride was grown in the same manner as in Example 1 except that commercially available hydrazine was used without purification. The electrical properties of this crystal were measured by the four-terminal method. As a result, the compound semiconductor is n-type, the electron concentration at room temperature is 2 × 10 ²⁰ / cm ³ , and the electron mobility is 5 c.
It was m ² / Vsec.

[0016]

According to the epitaxial vapor deposition method of the present invention, it is possible to obtain a high-quality nitrogen-containing 3b-5b group compound semiconductor. A light-emitting device manufactured using the compound semiconductor has high emission efficiency.

[Brief description of drawings]

FIG. 1 is a schematic view of an example of an apparatus used in the vapor phase growth method of the present invention.

[Explanation of symbols]

 1 mass flow controller 2 thermostat 3 TMG bubbler 4 mass flow controller 5 thermostat 6 hydrazine bubbler 7 reactor 8 external coil for high frequency heating 9 susceptor 10 substrate 11 exhaust hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadaaki Yako 5-1, Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Co., Ltd. Within the corporation

Claims (2)

[Claims] 1. A method of epitaxial vapor phase growth of a 3b-5b group compound semiconductor containing nitrogen as a 5b group, wherein at least hydrazine is used as a nitrogen source and the water content of the hydrazine is 100 ppm by weight or less. A method of epitaxial vapor deposition of a 5b group compound semiconductor. 2. A 3b-5b group compound semiconductor is In _x Ga.
_y Al _z N (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦
1. The method for epitaxial vapor phase growth of a 3b-5b group compound semiconductor according to claim 1, which is a compound semiconductor represented by the formula 1, x + y + z = 1).