JPS62154721A - Formation of semiconductor single crystal thin film - Google Patents

Abstract

PURPOSE:To form a semiconductor single crystal thin film insulatedly isolated from a semiconductor substrate on insulating layers on the surface of semiconductor substrate by a method wherein the second semiconductor layer is formed on the first semiconductor substrate and the first insulating layers and after removing the second semiconductor layer formed on the first semiconductor substrate, the second insulating layers are formed on the surface of the first semiconductor substrate to form the second semiconductor layers again on the second insulating layers. CONSTITUTION:Within the first epitaxial growing process to form the second semiconductor layer 3 [Ga(Al)As layer] on the first semiconductor (silicon) substrate 1 and the first insulating layers (SiO2) 2, proper single crystal semiconductor layers 3A are grown on the semiconductor substrate 1 while similar single crystal semiconductor layers 3B are formed on the second insulating films 2 by lateral (in the sideward direction) growing process. Furthermore, within the second epitaxial growing process to form the second semiconductor layers 3C on the second insulating films 2' previously formed, the single crystal semiconductor layers 3C are formed by laterally growing the former single crystal semiconductor layers 3B again. Resultantly, a semiconductor single crystal thin film 4 [Ga(Al)As] isolated from the semiconductor substrate 1 by the insulating layers 2, 2' can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a semiconductor single crystal thin film on a semiconductor substrate, which is separated by an insulating layer.

[Summary of the invention]

The present invention provides a method for forming a semiconductor single crystal thin film, in which a first insulating layer is selectively formed on a semiconductor substrate, a semiconductor layer is formed on the semiconductor substrate and the first insulating layer, and then the semiconductor layer is formed on the semiconductor substrate. By removing the semiconductor layer formed above, then forming a second insulating layer on the surface of the semiconductor substrate from which the semiconductor layer has been removed, and forming the semiconductor layer on this second insulating layer, the semiconductor substrate is It is possible to form semiconductor single-crystal thin films separated by insulating layers.

[Conventional technology]

Ga(As) epitaxial growth on a silicon substrate is performed using a GaAsP/GaP superlattice.
There are a method of using e as a buffer layer, a method of directly growing GaAs by slow growth, etc. On the other hand, Ga
When selectively growing single crystal GaAs on an As substrate through a mask of an insulating film such as 5i02 or SiNx, M
In the BE (molecular beam epitaxy) method, polycrystalline GaAs is deposited on the insulating film, and in the MOMBE (organo-metallic molecular beam epitaxy) method and the reduced pressure CVD (metal-organic chemical vapor deposition) method, nothing is deposited on the insulating film. Does not accumulate. Also, normal pressure MOC
It has been reported that in the VD method, particles are deposited on the insulation crotch unless the growth conditions are strict. Under strict growth conditions, some lateral growth occurs on the insulating film, but lateral growth of sufficient length cannot be obtained.

No method has yet been proposed for growing an m-v group compound semiconductor single crystal thin film, such as a Ga(ΔA)As single crystal thin film, on an insulating film such as 5iOz or SiNx.

[Problem that the invention seeks to solve]

By the way, for example, m separated by an insulating layer on a silicon substrate
If a -v group compound semiconductor single crystal thin film can be formed, a composite device of a silicon-based element and an m-v group compound semiconductor-based element can be obtained. For example, if a silicon single crystal thin film separated by an insulating layer can be formed on a silicon substrate, application to three-dimensional devices becomes possible.

In view of the above-mentioned points, the present invention provides a method for forming a semiconductor single crystal thin film, which can form a semiconductor single crystal thin film with an insulating layer on a semiconductor substrate.

[Means for solving problems]

The present invention provides a method for selectively disposing a first semiconductor substrate (1) on a first semiconductor substrate (1).
An insulating layer (2) is formed, and the first layer is epitaxially grown.
A second semiconductor 1i (3) is formed on the semiconductor substrate (1) and the first insulator j# +21 ). Next, the second semiconductor layer (3Δ) formed on the first semiconductor substrate full is selectively removed, and a second semiconductor layer is formed on the surface of the first semiconductor substrate in the area where the second semiconductor layer (3A) is removed. A second insulating layer (2') is formed. Thereafter, the second semiconductor layer (3C) is again formed on the second insulating layer (2') by epitaxial growth.

[Effect]

A second insulating layer (2) is formed on the first semiconductor substrate (11) and the first insulating layer (2).
In the first epitaxial growth step to form the semiconductor layer (3), the original single crystal semiconductor layer (3A) grows on the semiconductor substrate (1), and the lateral (lateral direction) grows on the second insulating layer (2). ) growth occurs and the single crystal semiconductor layer (3B
) is formed. Further, after forming the second insulating layer (2'), a second insulating layer (2') is formed on which a second semiconductor layer (3C) is formed.
The first single crystal semiconductor in the epitaxial growth process! (3
From B), the single crystal semiconductor layer (3C) is grown laterally again.
is formed. As a result, an insulating layer (
Semiconductor single-crystal thin l1IA (4
) is formed.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

Embodiment 1 First, as shown in FIG. 1A, 5i (hl5(2)) is selectively formed on the surface of a group III semiconductor, for example, a silicon substrate (1), by selective oxidation (LOGO5).

Next, as shown in FIG. 1B, 5iO2Jti((
21 (for example, VPE on 11)
(vapor phase epitaxy) method, LPE (liquid phase epitaxy) method, normal pressure MO
An m-v group compound semiconductor, such as a Ga(i)As layer (3), is epitaxially grown by CVD (metal-organic chemical vapor deposition) or the like. At this time, Ga (AI) and A
The S layer (38) is epitaxially grown. In addition, lateral growth occurred and single crystal Ga also formed on 5i(h #(2)).
(8!!,) 8s'FA (3B) grows.

Next, as shown in FIG. 1C, only the Ga(Al)As layer 4 (3B) on the 5iOz JBf2) is left and the other Ga(Al)As layer (3A) is selectively removed by etching. Next, as shown in the first diagram, the 5i02 layer (
5io2 layers (2') are selectively formed on all parts of the silicon substrate (1) that are not covered by 21. Ko (7) 5
in2. For forming rtf (2'), for example, the Ga (AI) As layer (3B) is covered with an oxidation-resistant film using a conventional method, and then the whole is thermally oxidized.

Thereafter, Ga (Aff) As is epitaxially grown again using the above method to form a Ga (Aff) As layer (3
5i02E by lateral growth again using 0) as seeds.
(2') J2 single crystal Ga (Aff) As1
Form ei (3C). In this case, Ga (A
l) Because the As layer (3B) is formed, the overall G
a (AJ) The As layer is somewhat uneven.

Therefore, after this, the surface of the Ga (Aff) As layer can be flattened. As a result, as shown in Figure 1, 5i02 layers (2) (2') are formed on the silicon substrate (11).
is formed, and Ga(A) separated from the substrate (1) is formed on it.
β) Semiconductor substrate on which As single crystal thin film (4) is formed (
6) is obtained.

Example 2 In the example shown in FIG. 2, the method of forming the 5i02 layer is different from that shown in FIG.

First, as shown in FIG. 2A, a silicon substrate (5
After depositing the i02 layer (2), the 5i(h layer (2)) is etched away in a predetermined pattern.

Next, as shown in FIG. 2B, the silicon substrate (1) on which 5i(h!(2) is selectively formed) is subjected to, for example, VPE.

Ga (
All> As layer (3) is epitaxially grown.

Next, as shown in Figure 2C, the Ga (An or As) layer (38) on the area where the 5i02 layer (2) is not formed is removed by selective etching.
iO2 is redeposited and a 5i02 layer (2') is deposited on the silicon substrate (1) exposed by selective etching removal. At this time, it is conceivable that SiO2 is also deposited on the side surfaces of the Ga layer (3B).

In this case, the 5i02 deposited on the side surface of the Ga (AJ2) As layer (3B) is removed by anisotropic etching such as ion milling or reactive ion etching.

Next, as shown in Figure 2, Ga (A1.) A
The s-layer is grown epitaxially, and Ga(Al)A
By lateral growth using the s layer (3B) as a seed 5i02
An S layer (3c) is formed on the layer (2') using single crystal Ga (8l). After this, the Ga (Aj and As layers) are planarized.

This results in a silicon substrate (11 on 5i02! (21
(2') is formed, and a semiconductor substrate (6) is obtained on which a Ga (AI) /ls single crystal thin film (4) separated from the substrate (1) is formed.

According to this method, Ga (AJ2) is deposited on the SiO2 layer.
Single-crystal growth of As is possible, and arbitrary GaAs-based elements can be created on a silicon substrate. In addition, an inexpensive silicon substrate of good quality and excellent heat resistance can be used, and it is possible to fabricate a Si-based element and a GaAs-based element on the same substrate. GaAs-based elements include laser diodes,
Outside of light emitting diodes, solar cells, and field effect transistors 2
High mobility device using dimensional electron gas channel (
IIEMT, TEGFET), etc. can be considered.

Incidentally, in the above example, a group IV semiconductor-insulating layer-1n-v group compound semiconductor structure has been described, but it can also be applied to a group IV semiconductor-insulating layer-1v group semiconductor structure.

Further, in the above example, Sio2 is used as the insulating layers (2) (2'), but other insulating layers such as SiNx can also be used. Also, both insulating layers (2+(2') are the same 5i02
However, different insulating layers may be used.

〔Effect of the invention〕

According to the present invention, it is possible to form a thin semiconductor single-crystalline product on an insulating layer on the surface of a semiconductor substrate in a state insulated and separated from the semiconductor substrate. Therefore, for example, it is possible to form a Ga(Al)As single crystal thin film on a Si substrate with an insulating layer interposed therebetween. Applications to ICs and tertiary elements become possible.

Brief Description of the Drawings FIGS. 1A-E and 2A-E are process diagrams showing an embodiment of the method for forming a semiconductor single crystal a film according to the present invention, respectively.

(11 is a silicon substrate, (2) (2') is Sio2&,
(3) [(38') (3B) (3C) ) is G
a (Aj') AsFii, (4) is a S single-crystal thin 1 complex to Ga(1).

Claims (1)

[Scope of Claims] a. selectively forming a first insulating layer on the first semiconductor substrate; b. forming a second insulating layer on the first semiconductor substrate and the first insulating layer;
c. removing the second semiconductor layer formed on the first semiconductor substrate; d. the first semiconductor from which the second semiconductor layer has been removed; a step of forming a second insulating layer on the substrate surface, e.
forming the second semiconductor layer on the insulating layer.