JPH03188619A - Method for heteroepitaxially growing iii-v group compound semiconductor on different kind of substrate - Google Patents

Abstract

PURPOSE:To allow a III-V group compound making less dislocation to heteroepitaxially grow on a different kind of substrate by allowing to grow a buffer layer of a III-V group compound semiconductor doped with a specific element at a high concentration. CONSTITUTION:An undoped GaAs layer 13 is allowed to grow on an undoped GaAs buffer layer 12 by suppressing the occurrence of an anti-phase domain by heat-treating an Si (100) substrate 11 which is a different kind of substrate with an off-angle of 2 deg. in (001) direction and annealing the layer 12 after the layer 12 is allowed to grow under heat. Then a C-doped GaAs layer 14 is allowed to grow on the layer 13 and the buffer layer 14 of a GaAs 2 III-V group compound semiconductor layer doped with C at a high concentration is allowed to grow to a required thickness. When the buffer layer formed of the layers 12-14 is allowed to grow, the high-concentration dislocation produced at the boundary between the GaAs and Si disappears in the GaAs buffer layer due to the pinning by carbon and the III-V group compound semiconductor making less dislocation is allowed to heteroepitaxially grow, and thus, an AsGa grown layer 15 making less dislocation can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for heteroepitaxially growing a ■-v group compound semiconductor on a heterogeneous substrate such as a Si substrate.

[Conventional technology]

The growth of ■-V group compound semiconductors on heterogeneous substrates has been widely studied with the aim of applying them to solar cells, optoelectronic integrated devices, and the like. Among these, for example, there is a gap between the Si substrate, which is the most widely used substrate, and the ■-V group compound semiconductor.
Since aAs has a lattice mismatch of 4% and InP has a lattice mismatch of 8%, these cannot be epitaxially grown directly on a Si substrate. There is also the problem of warping and cracking due to differences in thermal expansion coefficients.

In order to solve these problems, various buffer layers are generally introduced.For example, Ga
In As/Si, Ga is grown at a lower temperature than the growth temperature of GaAs grown on the buffer layer.
As (Japanese Journal of Applied Physics, Volume 24, Page 843, 1984)
, Strained Superlattice (Applied Physics Letters 48
Volume 1223 Page] 986) etc. are used as a buffer layer. In addition, thermal cycle annealing (Applied Physics Letters, Volume 50, Page 31, Page 19)
1987) has also been reported to have a dislocation reduction effect.

[The problem that the invention aims to solve]

However, in either method, ■r
A high density of residual threading dislocations exceeding 106 CI11-' is present in the -v compound semiconductor growth layer.

An object of the present invention is to provide a method for heteroepitaxially growing a III-V compound semiconductor with few dislocations on a seed substrate.

[Means to solve the problem]

The heteroepitaxial growth method of the present invention consists of (1) a method in which a group V compound semiconductor growth layer is heteroepitaxially grown on a substrate of a different type other than the growth layer through one or multiple buffer layers, in which carbon is doped at a high concentration; (2) The method is characterized by a step of growing a buffer layer made of a V-group compound semiconductor.

[Effect]

In the heteroepitaxial growth method according to the present invention, first, a ■-■ group compound semiconductor buffer layer doped with carbon at a high concentration is grown on a substrate. The high concentration of dislocations generated at the interface between GaAs and Si are pinned by this carbon in the GaAs buffer layer and disappear.Here, since the carbon concentration in GaAs is several percent or more of the host atomic concentration, threading dislocations occur. There is a high probability that carbon impurities will hit carbon impurities. Therefore, the number of dislocations penetrating to the undoped GaAs layer grown on this buffer layer is reduced, resulting in a GaAs growth layer with low dislocations.Also, carbon impurities have a small diffusion coefficient, so Diffusion from the heavily doped buffer layer to the undoped layer is also small, making it excellent for device applications.

〔Example〕

The present invention will be described in detail below using the drawings.

FIG. 1 is a growth process diagram illustrating an embodiment of the present invention. In this example, a Si (100) substrate 11 with a 2° off angle in the <001> direction is heat treated at a high temperature of 900°C. This allows the anti-phase domain (
antiphase domains). Three undoped GaAs buffer layers 12 are formed on this substrate.
After growing 1100 nm at 00° C., annealing at 600° C. for 15 minutes (FIG. 1(a)), then growing an undoped GaAs buffer layer 13 at 450° C. for 1100 nm, and then growing carbon (C) at 5×10 A GaAs buffer layer 14 doped with "am" is grown to a thickness of 1 μm (FIG. 1(b)). Thereafter, the growth temperature was set to 500° C., and an undoped GaAs layer 15 was grown to a thickness of 3 μm (the first C-doped GaAs buffer layer 14 was grown using trimethyl gallium
x (Ga (CH3)3) and arsine (AsH3)
The undoped GaAs layer was grown by switching between triethylgallium (Ga(CzHl)) and arsine. In this example, dislocations were reduced by a GaAs buffer layer doped with a high concentration of carbon. Due to the effect of
-', a GaAs grown layer with lower dislocations than the conventional one was obtained.

In the above embodiment, chemical beam epitaxy was used for the buffer layer and the growth layer, but other growth methods such as organometallic vapor phase epitaxy, molecular beam epitaxial growth, etc. may also be used.

Although the above embodiment describes the growth of GaAs on a Si substrate, the present invention can also be applied to the growth of InP.

In that case, after growing GaAs on the Si substrate as described above, InP doped with a high concentration of carbon may be sandwiched on the GaAs as a buffer layer between GaAs and InP.

Although thermal cycle annealing was not performed in the above examples,
Of course, these methods can also be used in combination. Although the strained superlattice buffer layer is not used in the above embodiment, it is of course possible to use this buffer layer at the same time. In the above embodiment, carbon is doped as an impurity, but other impurities, For example, silicon (St) and carbon may be doped simultaneously.

〔Effect of the invention〕

In the epitaxial growth method according to the present invention, by forming a buffer layer in which a high concentration of carbon is doped into an I[IV group compound semiconductor, impurity atoms have the effect of pinning dislocations caused by lattice mismatch and differences in thermal expansion coefficients. Low dislocations can be obtained in the ■-■ group compound semiconductor grown on a heterogeneous substrate.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the process of growing GaAs on Si according to an embodiment of the present invention. In the figure, 11...<001>
5i (100) substrate 2° off in the direction, 12...low temperature grown undoped GaAs layer, 13... undoped G
aAs layer, 14... carbon-doped GaAs layer, 15
. . . each shows a long undoped GaAs layer. Atsushi Atsushi (α) (b) Closed J

Claims (1)

[Claims] Growing one or more buffer layers on a heterogeneous substrate made of constituent elements other than the III-V compound semiconductor growth layer,
The method for heteroepitaxially growing a III-V compound semiconductor on the buffer layer is characterized by the step of growing a buffer layer made of a III-V compound semiconductor doped with carbon at a high concentration. A method for heteroepitaxial growth of III-V compound semiconductors on heterogeneous substrates.