JPH02109320A - Manufacture of heteroepitaxial film - Google Patents

Abstract

PURPOSE:To provide a heteroepitaxial film having a low dislocation density using a simple method by forming a three- or four-dimensional mixed crystal buffer layer having a grating constant in the same degree as the desired epi. layer, and thereupon allowing an epi. layer to grow. CONSTITUTION:On an Si substrate an InxGa1-x-yAlyP buffer layer 2 is grown at a temp. of 560 deg.C by the use of InGa alloy. In, Al as the III group source and red phosphorus as the V group source, where x and y are determined so that the grating constant becomes in the same degree as that of GaAs. This is followed by grown of an approx. 3mum GaAs layer 3 at the same temp. This decreases the dislocation density in the epi. layer to 1/10<2>-10<3> of normal value, to enable manufacture of heteroepitaxial film with a low dislocation density by simple method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a heteroepitaxial thin film,
More specifically, the present invention relates to a method of manufacturing a heteroepitaxial thin film having a low lattice defect density and having a lattice constant substantially different from that of a substrate.

[Prior Art] Until now, the growth of an epitaxial thin film with a lattice constant significantly different from that of a substrate, such as a GaASi film on a Si substrate, has been
, mMOCVD method, MBE method, etc., and a method called a two-step growth method. In this method, a thin buffer layer is first grown at low temperature and humidity. Misfit dislocations are introduced into the interface between the buffer layer and the substrate, the stress due to the difference in lattice constant between the epitaxial layer and the substrate is relaxed, and the lattice of the buffer layer returns to its original lattice. Therefore, on top of this buffer layer,
Epitaxial layers can be easily grown at normal high growth temperatures.

[Problems to be Solved by the Invention] However, the epitaxial thin film grown in this manner has a very large number (109 to 108 cm-2) of dislocations. Some of these dislocations are ends of misfit dislocations, and others are caused by local stress concentration during growth.

In order to reduce the dislocation density in this epitaxial layer, a strained superlattice can be added during epitaxial layer growth,
Attempts have been made to perform heat treatment after growth, and in epitaxial layers subjected to various treatments in this way, the dislocation density is 106Crn-2.

However, increasing the strained superlattice by 1J11 or performing heat treatment has the disadvantage of making the 3i method for producing a heteroepitaxial 1-Nor layer extremely complicated.

It is an object of the present invention to provide a simple method for producing a low-dry film 171 and a one-time tero-T pitaxial thin film that solves these problems.

[Means for Solving the Problem] The present invention provides a method for manufacturing a heteroepitaxial thin film by performing heteroepitaxial X-L growth on a substrate having a different lattice constant, in which an epitaxial layer to be formed later and an epitaxial layer to be formed later are formed on the substrate. The method is to grow a ternary or quaternary mixed crystal buffer having a similar lattice constant, and then grow a desired epitaxial layer on the buffer. This is a manufacturing method.

[Function] IntxGaxAs of ternary mixed crystal, Ga1- of quaternary mixed crystal
8 Shima As i-y py, In1. Ga, As
In i-y py, the critical pus for misfit dislocation generation is 2-3 compared to binary compounds such as GaAs and Ir+P.
Known to be twice as sensitive (Physica status)
solid day.

(a) 70. 277 (1982): Journal of Applied Fixtures, 52.4575 (1
981) ). This indicates that the yield stress in the crystal increases as the crystal becomes a multicomponent mixed crystal.
There is. In other words, this means that if the same stress is applied,
It is thought that dislocations are less likely to occur in multi-component mixed crystals.

Therefore, by using a multi-component mixed crystal buffer layer, it is possible to reduce the dislocation density that occurs in the buffer diagram, and it is possible to reduce the dislocation density that propagates upward to the epitaxial layer that grows on it. .

[Example] Next, an example of the present invention will be described in detail with reference to the drawings.

In this example, growth of GaAs on Si where InxGa1-x-ρV, P is a buffer Q and 1- will be described. FIG. 1 shows a schematic cross-sectional view of the heteroepithelial layer formed according to this embodiment.

Decabitaxial growth was performed by MBF.

First, the first surface of the 31st base plate was prepared using the method of Ishiita et al. (collective 1-
The substrate temperature was then increased to 560°C.
The group ■ sources include I I'l Ga alloy and In
and M metals, red phosphorus is used as the VK source, and In
xGa1-x-, H town P buffer layer 2 was grown. x,
The composition of y is a value grown on caAs in advance and confirmed that Δa/a is smaller than 1X10-3,
In this example, x=0.47. y=0.11. Note that a is the lattice constant of GaAs, and Δa is the difference in the lattice constants of GaAs and InxGa1-x-VM,P.

0. Approximately 2000 InxGa1 with growth gm of Qm/h
-x, M, P buffer shrine 2 was grown. Next, a GaAs layer 3 was grown for about 3 μs at the same temperature.

The surface of the GaAS layer 30 grown in this manner was etched with molten KOH at 0° C. for 20 seconds, and the dislocation density on the surface of the GaAS layer was evaluated and found to be 10 Cm'-2.

This value was 2 to 3 orders of magnitude lower than when GaAS was grown directly on a Si substrate by a normal two-step growth method. This result shows that InxGato, -yMVP buffer 1
This can be thought to be due to a decrease in the dislocation density within the Karanai region.

[Effect of the invention 1 As explained above, the dislocation density in the epitaxial layer produced by the method of the present invention is 1
0" to 1/103, and without adding a strained superlattice or heat treatment as in conventional methods,
A heterotaxy cell film with a low dislocation density can be manufactured by a simple method.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a heteroepitaxial layer obtained according to an embodiment of the present invention. 1...Si substrate 2...In, Ga1-x-yMy 3...GaA three-layer buffer layer agent

Claims (1)

[Claims] (1) In a method for manufacturing a heteroepitaxial thin film that involves performing heteroepitaxial growth on a substrate with a different lattice constant, a ternary or quaternary mixed crystal having a lattice constant comparable to that of an epitaxial layer to be formed later is formed on the substrate. 1. A method for producing a heteroepitaxial thin film, which comprises growing a buffer layer and then growing a desired epitaxial layer on the buffer layer.