JPH033363A - Manufacture of semiconductor thin film - Google Patents

Abstract

PURPOSE:To obtain a method wherein problems of crystal defect and surface roughness caused by lattice unconformity are solved, by a method wherein an InP single crystal layer is grown after a specified buffer layer is formed on an Si substrate, thereon an InP single crystal layer is grown and heat-treated, and thereon a GaInAsP multilayer film whose lattice constant is changed stepwise is grown. CONSTITUTION:On an Si substrate 1, amorphous or polycrystalline GaAs buffer layer 2 and InP buffer layer 3 are formed in order; an InP single crystal layer 4 is grown on the InP buffer layer 3, and heattreated in a PH3 atmosphere. After a GaInAsP multilayer film 5 whose lattice constant is changed stepwise is formed on the InP single crystal layer 4, an InP single crystal layer 6 is grown on the GaInAsP multilayer film 5. For example, the above GaInAsP multilayer film 5 is grown first by using GaInAsP whose lattice constant is nearly equal to that of the InP layer 4, and then grown to be a multilayer whose lattice constant approaches the original lattice constant of InP. The thickness of each layer is made so thin that lattice defect does not occur even if lattice discrepancy exists. For example, the thickness is about 10-100Angstrom .

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention is a method for manufacturing single crystal In with few crystal defects on an S# substrate.
The present invention relates to a method for manufacturing a semiconductor thin film in which P is grown.

(Prior art) Conventionally, this type of crystal growth method has been described in IK 33rd Applied Physics Conference Proceedings, p. 723, 4P-W-2 (1986
There is one that will be disclosed in the spring of 2018, and it will be briefly explained below using the diagram.

This growth method is called metal organic vapor phase epitaxy (MOVPE), which uses a hydrogen compound and an organic metal as raw materials and utilizes a thermal decomposition reaction.
? 1etal Organic Vapor Pha
se Epitaxy or MOVPE: Met
al Organic Chemical Vappo
This is a method using

As shown in FIG. 2, the St substrate 11 has a (100) surface.
On top is triethyl indium (T E
Single crystal InP12 is directly grown using phosphine (PHI) as a raw material for I, (cAL)sin) and P.

(Problem S to be solved by the invention) However, in the above growth method, since InP12, whose lattice constant is approximately 8% larger than that of Si, is directly grown, many crystal defects occur due to this lattice mismatch. do.

Additionally, there is a problem in that it is difficult to obtain a crystal with a flat, mirror-like surface.

This invention solves the problems of the above-mentioned prior art.
The present invention provides a method for manufacturing semiconductor 1III1 that solves the problems of frequent occurrence of crystal defects due to lattice mismatch and surface roughness.

(Means for Solving the Problems) The present invention provides a method for manufacturing a semiconductor thin film, including a step of sequentially forming an amorphous or polycrystalline GaAs buffer layer and an I+lIP buffer layer on an Sl substrate, and
This method introduces the steps of growing an 877P single crystal layer on P Bacifern and heat-treating it in a PKs atmosphere, and forming a GaInAsP multilayer film with a stepwise change in lattice constant on this InP layer. be.

(Function) The present invention introduces the above-mentioned steps into a method for manufacturing a semiconductor MLL, and thus forms an amorphous or A state in which the crystallinity of the InP single crystal layer is improved by making it polycrystalline and flattening it even on a Si substrate with a different lattice constant, and growing an InP single crystal layer on this and heat-treating it in a PH atmosphere. The lattice constant of GaInAsP is approximately equal to that of this InP single crystal layer.
Multilayer films can be grown, thus eliminating the aforementioned problems.

(Example) Hereinafter, an example of the method for manufacturing a semiconductor thin film of the present invention will be described based on the drawings.

FIG. 1 shows a cross section of a crystal structure when a single crystal InP layer is grown on a Si substrate according to the present invention.

Same as conventional MOVPH method and molecular beam growth method (MBE)
: Plolecular Beam Epltaxy)
However, in this example, a method using N0VPE will be described.

First, on the St substrate 1 having a (100) crystal plane on the surface,
A GaAs buffer JI2 and an InP buffer layer 3 are formed by the following method, and an InP single crystal 4 is grown.

This method is described in the literature Journal of Cryst
al Growth.

vat, 93. (19BB) Nos. 523 to 526 J.

First, Sl group! j1 is chemically etched (removal of surface oxide with hydrofluoric acid) and introduced into a growth apparatus.

Next, the surface is cleaned by heating to 1000° C. or higher in an arsine (AsHs) atmosphere.

Next, using AsB5 and triethyl gallium (TEG) as raw materials, GaAs8777
Grow layer 2.

Furthermore, T
An IfiP buffer layer 3 having a thickness of 2 Onm or less is grown using MI and PHa.

Since these two buffer layers are grown at a temperature lower than the normal growth temperature of GaAs and InP (600° C. to 750° C.), they do not become single crystal but become polycrystalline or amorphous.

Therefore, a flat layer can be obtained even on a Si substrate with a different lattice constant (however, there are many crystal defects and poor crystallinity).

Next, a single crystal of the InP single crystal layer 4 is grown at a normal IMP growth temperature (600° C. to 700° C.).

Thereafter, the crystallinity of the InP single crystal layer 4 is improved by heat treatment at 730 to 780° C. in a Pyls atmosphere.

However, since the lattice constant of InP is 8% larger than that of St, the lattice constant of the InP single crystal layer 4 is smaller than its original lattice constant.

Therefore, next, a GaInAsP multilayer film 5 was grown, and an IrAsP multilayer film 5 was grown.
+P single crystal layer 6 is grown to a desired thickness.

This GaInAsP multilayer film 5 first uses GaInAsP whose lattice constant is approximately equal to that of the InP layer 4, and then the original I
It grows in multiple layers so that the lattice constant approaches that of nP.

The thickness of each layer is made thin enough that even if there is lattice misalignment, no lattice defects will occur. For example, 10 to 100
Make it personal. In addition, the number of layers is IN or more (in the case of 1 layer, In
The number of layers is determined to be an appropriate number (so that the lattice constant is between the values of the P single crystal layer 4 and the InP single crystal layer 6).

(Effects of the Invention) As described above in detail, according to the present invention, first, a GaAs buffer layer and an InP layer are formed on a Si substrate.

After growing the phase layer in polycrystalline or amorphous form, InP
After forming the single crystal layer, a GaInAsP multilayer film was grown on top of it to compensate for the lattice mismatch difference, so the InP single crystal layer above it had fewer crystal defects than before. , the surface flatness is expected to be good.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor thin film manufactured by an embodiment of the semiconductor thin film manufacturing method of the present invention, and FIG. 2 is a cross-sectional view of a conventional semiconductor thin film. 1...5ill, 2...GaAa buffer eyebrow, 3.
...InP buffer layer, 4,6...InP single crystal layer,
5...Ga1n^3P layer.

Claims (1)

[Claims] (a) Amorphous or polycrystalline Ga on a Si substrate
a step of sequentially forming an As buffer layer and an InP buffer layer; (2) a step of growing an InP single crystal layer on the InP buffer layer and heat-treating the layer in a PH atmosphere; (c) a step of forming the InP single crystal Ga layer with stepwise changes in lattice constant
(2) the step of forming an InAsP multilayer film; and (2) the step of forming an InAsP multilayer film;
A method for manufacturing a semiconductor thin film, comprising the steps of growing an InP single crystal layer on an nAsP multilayer film.