JPS61247686A - Preparation of semiconductor single crystal - Google Patents

Abstract

PURPOSE:To easily add N2 to a desired concentration at low temp. in a process for the epitaxial growth of a semiconductor single crystal by a vapor growth method of an organometallic compd. by adding nitrogenous impurity generated by the decomposition of NH3-contg. gas by irradiating with light. CONSTITUTION:A susceptor 2 supported by a rotary shaft 5 is provided in a tubular reaction vessel 1 and a substrate 3 for growing a single crystal is placed on the susceptor 2; the substrate 3 is held at an appropriate temp. by heating with a high frequency coil 4. Then, an organometallic compd. and a metal hydride are fed as starting material gas from an introducing hole 6 for the starting material gas 7, which are thermally decomposed on the substrate 3 to form epitaxial growth layer. At the same time, gaseous NH3 10 is fed from an introducing hole 9 of the impurity starting material gas, and the NGH3 gas is irradiated with ultraviolet rays generated by an ultraviolet ray generator 11 through a light introducing window 12. Thus, the NH3 is decomposed and N2 is added to the epitaxial growth layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a metal organic chemical vapor deposition (MOCVD) method (a method for growing an epitaxial layer containing impurities on a substrate).

[Technical background of the invention and its problems]

The method for manufacturing epitaxial layers that utilizes the thermal decomposition reaction between a growing metal compound and a metal hydride is referred to as the MOCVD method, and since all raw materials are supplied in gaseous form, it is possible to control the thickness and composition of the epitaxial layer. It is easy to use, and as a promising method for production, it is being put into practical use.

By the way, n-via compounds such as ZnS and Zn5e are attracting attention as materials for emitting light-emitting devices, but it is difficult to obtain compounds exhibiting p-type conductivity, and p-n junctions have not been widely developed. For this reason, an efficient blue light photoconductor has yet to be realized. The reason for this is thought to be that even if an acceptor impurity is added, the j:9 deficiency is compensated for by 111f3. Therefore, MOC that can be grown at low temperature
Attempts have been made to grow ■-■ group compound crystals by suppressing the generation of defects using the VD method (2).An attempt has also been made to add nitrogen as an acceptor impurity using ammonia gas. Although it has been confirmed that a shallow acceptor level is formed in
This is thought to be due to the fact that ammonia gas is not decomposed sufficiently at a growth temperature as low as C, and the amount of B accumulated in the growth layer is small.

[Purpose of the invention]

In order to solve the above-mentioned problems, the present invention has been developed by making it possible to add nitrogen impurities of high concentration in low-temperature growth (2). The object of the present invention is to provide a method for manufacturing epitaxial J- exhibiting p-type conductivity.

[Summary of the invention]

The present invention relates to a method for epitaxially growing single crystals by metal organic vapor phase epitaxy, in which a gas containing ammonia (
- A method for manufacturing a semiconductor single crystal characterized by light irradiation (secondarily promoting the decomposition reaction of ammonia and adding a desired concentration of nitrogen to the epitaxial growth layer).

〔Effect of the invention〕

The method of the present invention (Secondly, it is possible to add a desired degree of nitrogen without raising the temperature (secondarily, the generation of defects can be suppressed, so it is possible to obtain p-type conductivity by adding a II-VI group compound crystal (-)). This is effective in realizing a highly efficient neck color vision element.

[Embodiments of the invention]

Hereinafter, the present invention will be explained from the second embodiment using the drawings.

Figure 1 is a diagram showing an example of a growth apparatus used in the method of the present invention.
is placed on the susceptor 2 (the single crystal substrate 3 is fixed on the susceptor 2).The susceptor 2 is heated by the frequency coil 4,
The substrate 3 is maintained at an appropriate temperature. When an organometallic compound and a metal hydride are supplied as a source gas 7 through the source gas introduction hole 6, a thermal decomposition reaction occurs on the substrate 3, and an epitaxial layer grows.

At the same time, υ ammonia gas IO is supplied through the impurity raw material gas introduction hole 9.The impurity raw material gas introduction hole 9 (= is a blur of the light introduction window 12.This window 12 is made of a material through which ultraviolet rays easily pass through. For example, it is made of transparent quartz or the like.
Ammonia gas (double-layer injection) through 2.

Figure 1 (2) using the apparatus shown on a GaAs substrate (2 Zn5e
An epitaxial layer was grown. 2! [ii] The plate mW was set at 350° C., (CHs)tZn and H2Se were supplied as raw material gases, and (2NH) gas was supplied as additive impurity raw materials to grow a Zn5e layer of 4 μm.

When the electrical properties of the grown Zn5e layer were evaluated, it was found that it had high resistance without light irradiation, but at 300 nm
In the case of irradiation with light containing short wavelength components, a material exhibiting p-type conductivity was obtained. However, 300 nm
When irradiated with light that only contained longer wavelength components, the resistance remained high, similar to when no light was irradiated.

Furthermore, Fig. 2 shows the apparatus shown in Fig. 1 (=), and the light irradiation is performed on the gas near the substrate (2 times).
When the same growth as described above was carried out using the reaction vessel 13 (equipped with a two-light inlet 14), exactly the same results were obtained.

In the detailed description of the present invention, V/u was used to explain the production of Zn5e crystals, but it goes without saying that the production of other crystals such as ZnS and mixed crystals thereof (binary use is also possible).

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention (a schematic cross-sectional view of a plate manufacturing apparatus), and FIG. 2 is a schematic cross-sectional view of another embodiment of the present invention (a plate body manufacturing apparatus 1, 13, etc.) Reaction container, 2... Susceptor, 3
...Substrate, 4...High frequency coil, 5
...rotating shaft, 6...raw material gas introduction hole,
7... Raw material gas, 8... Exhaust hole, 9.1
5... Impurity raw material gas introduction hole, 10... Ammonia gas, 11... Ultraviolet generator, 12... Light introduction window. Agent: Patent Attorney Noriyoshi Chika Right (and 1 other person) Figure 1 Figure 2

Claims (3)

[Claims] (1) A method for producing a semiconductor single crystal, which is characterized in that a semiconductor single crystal is epitaxially grown by organometallic vapor phase epitaxy, the method comprising adding a nitrogen impurity to a gas containing at least ammonia by irradiating it with light. (2) The method for manufacturing a semiconductor single crystal according to claim 1, wherein the irradiated light is light containing a wavelength component shorter than 300 nm. (3) The method for producing a semiconductor single crystal according to claim 1, wherein the semiconductor single crystal is a II-VI group compound single crystal or a mixed crystal thereof.