JPH0475327A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a semiconductor layer whose quality is good and whose area is wide by a method wherein an insulating layer which has been formed on one face of a semiconductor substrate is etched selectively, the semiconductor substrate is exposed, the window by an exposed part is used as a seed crystal, a thin and wide semiconductor layer is formed on the insulating layer in the transverse direction by a liquid growth method and a semiconductor layer is then formed additionally on it by a vapor growth method. CONSTITUTION:The surface of a semiconductor Si substrate 10 is oxidized or a film formation technique such as a CVD technique or the like is used; an SiO2 layer is deposited on the substrate 10. Thereby, an insulating SiO2 layer 11 is formed. Then, the SiO2 insulating film 11 is etched by a photolithographic process. The Si substrate 10 is revealed at a prescribed part 12; the exposed part (so-called window) 12 is used as a seed crystal for a liquid growth operation. After that, an Si single-crystal layer 13 is grown on the substrate by a liquid growth method using Sn as a solvent. The Si single-crystal growth layer 13 has a wavy pattern which is dependent on whether the insulating film exists or not on the substrate or which is specific to a liquid growth layer. Therefore, the surface of the semiconductor growth layer 13 is coated with a substance whose flattening property is good, e.g. with a resist for photolithographic use; the layer is then etched under a condition that an Si single crystal does not have any selective ratio; the layer is flattened; after that, an Si single crystal layer 14 is formed on the flattened liquid growth layer by a vapor growth method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method for forming a so-called SO tank structure, which is used in a method for manufacturing a semiconductor device.

[Conventional technology]

Conventionally, liquid phase epitaxy and vapor phase epitaxy have been widely used to form semiconductor layers. In the liquid phase growth method, a raw material for a semiconductor layer is dissolved in a liquid metal solvent at a high temperature to a 0-1 saturation state, and then the temperature is lowered to bring the solution to a predetermined supersaturation state. This supersaturated solution is then transferred onto the semiconductor substrate and the solution is allowed to cool. As a result, a semiconductor is deposited on the surface of the substrate, and when cooling is continued, a semiconductor layer is formed on the substrate. Afterwards, when the solution is separated from the substrate at a predetermined temperature, the growth is completed.

Since this liquid phase growth method has good surface morphology, a thin semiconductor layer can be formed on the insulating film.

On the other hand, as mentioned above, the temperature and composition of the liquid in the liquid phase growth method constantly change during growth, so the controllability of the composition in the depth direction of the grown layer is poor. Furthermore, the semiconductor growth layer contains solvent metal on the order of %, and the surface flatness of the growth layer is also poor.

Next, in the vapor phase growth method, a semiconductor raw material diluted with carrier gas is continuously introduced into a high-temperature reaction tube, where a chemical reaction occurs and a semiconductor layer is grown on the substrate. Incidentally, reaction products and unreacted raw materials are exhausted. In this way, it is possible to keep various reaction conditions such as the temperature, pressure, and gas composition in the reaction tube constant. Therefore, the properties of the growth layer in the depth direction are also constant. Furthermore, by changing the growth conditions, the properties of the growth layer in the depth direction also change depending on the growth conditions. Due to this, the vapor phase growth method has the advantage of good controllability. By the way, it is difficult to form a wide semiconductor layer on an insulating film using the vapor phase growth method.

[Problem to be solved by the invention]

As mentioned above, the liquid phase epitaxy method has good spreadability but the quality of the resulting semiconductor layer is poor, and the vapor phase growth method has the problem that the quality of the semiconductor layer is good but the spreadability is poor.

The present invention was made in view of the above-mentioned problems.
An object of the present invention is to obtain a method for manufacturing a semiconductor device that can form a high-quality, wide-area semiconductor layer on an insulating layer using a simple method.

[Means and effects for solving the problems] The method for manufacturing a semiconductor device according to the present invention uses an SO tank structure that forms a window to increase the width in the lateral direction using a liquid phase growth method, and then increases the growth depth using a vapor phase growth method. It is designed to grow with good controllability.

[Dormitory example]

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1(a) to 1(e) are cross-sectional views showing the manufacturing process of a semiconductor device according to an embodiment of the present invention.

First, the surface of the semiconductor Si substrate 10 is oxidized or CVD
Using film-forming techniques such as
insulating 5i02 layer (11) by depositing on
(See Figure 1 (8)).

Next, the 8i 02 insulating film (11) is etched using a photolithography process to form the 81 substrate (10) at predetermined locations (12).
expose. The exposed area (so-called window) (12) is used as a seed crystal for liquid phase growth (see FIG. 1(b)).

After this, S is grown on the substrate by liquid phase growth using Sn as a solvent.
i Grow the single crystal layer (13) (see Figure 1(c))
.

The Si single crystal growth layer (13) has a wave pattern peculiar to the presence or absence of an insulating film on the substrate or a liquid phase growth layer, so the semiconductor growth layer (13)
3) A material with good flatness, such as a photolithographic resist (1:1 resist), is etched on the surface under conditions that do not have the selectivity of Si single crystals (Fig. 1(d)).
)reference). Thereafter, as shown in FIG. 1 (fe), a Si single crystal layer (14) is formed on the flattened liquid phase by vapor phase growth.

〔Effect of the invention〕

As described above, according to the present invention, the SO tank structure is formed, and the ability to grow widely in the lateral direction using liquid phase growth and the ability to form a semiconductor layer with good properties using vapor phase growth are combined. This has the effect that high quality SOI can be formed.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(e) are cross-sectional views showing the manufacturing process of a semiconductor device according to an embodiment of the present invention. In the figure, (10)...Semiconductor substrate, 11...Insulating layer, 12...Window, 13...Liquid phase growth layer, 14...
- Vapor phase growth layer.

Claims (1)

[Claims] (1) forming an insulating layer on one side of a semiconductor substrate, selectively etching the insulating layer to expose the semiconductor substrate;
Using the window in the exposed portion as a seed crystal, a thin and wide semiconductor layer is laterally formed on the insulating layer by liquid phase epitaxy, and then a semiconductor layer is further formed on the semiconductor layer by vapor phase epitaxy. 1. A method of manufacturing a semiconductor device, characterized by forming a semiconductor device.