JPS6242556A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To simplify a process by implanting the ions of a substance forming an insulator with the constitient atoms of a semiconductor substrate to the surface of the semiconductor substrate, to which an ion implantation stopping film is shaped selectively, and thermally treating the semiconductor substrate. CONSTITUTION:Ion implanting stopping films 6 are formed selectively to the surface of an Si substrate 1. The ions of oxygen are implanted. Consequently, oxygen atoms are distributed to considerably deep 3a positions from the surface in regions in which there is no film 6 while they are distributed at positions in the vicinity 3b of the surface in regions in which there are the films 6. Si oxide films are shaped at the positions of 3a and 3b through the application of heat treatment. As a result, regions 1a are insulated and isolated completely by the Si oxide films 3a, 3b. According to the method, the films 3a are shaped at a position deeper than the surface in the regions in which there is no film 6, thus eliminating the need for epitaxial growth on the formation of a device. The films 3b as element isolation regions are flattened approximately to the region 1a, thus making processesing time remarkably shorter than a groove isolating method, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to semiconductor devices, particularly 5 silicon on In
5 Jator (hereinafter referred to as SOI).

2. Description of the Related Art A conventional SOI manufacturing method will be briefly described with reference to FIG. Oxygen atoms 2 are placed on the main surface of the silicon substrate 1 at 1o α
The ions are implanted at a position slightly deeper than the surface (Fig. 2a). Next, when a suitable heat treatment is performed, a silicon oxide film 3 is formed slightly deeper than the surface, as shown in FIG. 2, and the silicon layer 1a is slightly preserved on the surface.

Then, using the silicon layer 1& as a seed, an epitaxial layer 4 is grown (FIG. 2C). Next, an element isolation region 5 was formed to reach the silicon oxide film 3, and an active element was formed in the silicon region 4.

Problems to be Solved by the Invention However, such a conventional configuration has the problem that the process is complicated and the cost is high.

The present invention solves these problems and aims to simplify the process.

Means for Solving the Problem In order to solve this problem, the method for manufacturing a semiconductor device of the present invention selectively forms an ion implantation blocking film on the main surface of a silicon substrate, and oxygen atoms are removed from the ion implantation blocking film. The device action consists of implanting ions with sufficient energy to penetrate the silicon substrate and performing heat treatment.With this configuration, of the implanted oxygen atoms, those that penetrate the ion implantation blocking film are distributed on the ion surface of the silicon substrate. If the material is directly implanted into a substrate without a barrier film, it will be distributed quite deep from the surface of the silicon substrate, so the silicon oxide film formed by subsequent heat treatment will also form an isolation region at the same time. Therefore, the active region is completely isolated.

Embodiment FIG. 1 is a schematic cross-sectional view of an SOI manufactured according to an embodiment of the present invention. In FIG. 1, 1 is a silicon substrate, 6 is an ion implantation blocking film, and 3a and 3b are silicon oxide It is a membrane. A method for manufacturing an SOI having the structure shown in FIG. 1 will be described below.

First, a 1.5 μm thick silicon oxide film is grown on the surface of the silicon substrate 1, and selectively etched to form the ion implantation blocking film 6. Next, IMe
When oxygen ions of about 1018 crn-2 are ion-implanted with an acceleration energy of V, in the region where the ion-implantation blocking film 6 is not present, oxygen atoms are distributed at a position 3a considerably deep from the surface, while in the region where the ion-implantation blocking film 6 is In the area where
It comes to be distributed at position 3b near the surface. after that,
By applying appropriate heat treatment, a silicon oxide film is formed at the locations 3a and 3b. As a result, the silicon region 1& on the surface is completely insulated and isolated by the silicon oxide films 3a and 3b. Since oxygen atoms are implanted with enough energy to penetrate the ion implantation blocking film 6, the silicon oxide film 3 is formed at a position deeper than the surface in the region where the ion implantation blocking film 6 does not exist. The thickness of the silicon region 1a serving as the active region is approximately 0.5 .mu.m, and there is no need to perform epitaxial growth, which was performed in the conventional example, when forming a device. In addition, the silicon oxide film 3b serving as the element isolation region is formed in the silicon region 1a.
Since the surface is almost flat, the process is significantly shortened compared to methods such as groove separation.

Furthermore, the thickness of the silicon region 1a can be changed by changing the combination of the material and thickness of the ion implantation blocking film 6 and the implantation energy.

In this embodiment, oxygen was used as the implanted ion, but nitrogen may also be used. In that case, the insulator becomes silicon nitride, and it goes without saying that similar effects can be obtained.

Effects of the Invention As described above, the present invention improves the conventional method by ion-implanting a substance that forms an insulator with the constituent atoms of the semiconductor substrate into the surface of a semiconductor substrate on which an ion implantation blocking film is selectively formed. In comparison, the epitaxial growth process and element isolation process can be omitted, and the practical effects are outstanding, such as the element isolation region and active region are flattened.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an SOI manufactured according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional SOI manufacturing process. 1.4...Silicon substrate, 1a...Silicon region, 2...Ion implantation blocking film, 3a,
3b, 6...Silicon oxide film, 4a...
・Silicon layer, 6...Oxygen atoms, 7...
-Epitaxial layer, 8... Separation region. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 1-1-
Shi9ru Motoki 6--Tsujiiri 7! L + 1: Membrane f - 1 ゛ single life 1 release 5 - 11 minutes 4g 9 buttocks

Claims (1)

[Claims] A step of selectively forming an ion implantation blocking film on the main surface of the semiconductor substrate, and ion implantation of a substance that forms an insulator with the main constituent atoms of the semiconductor substrate with enough energy to penetrate the ion implantation blocking film. 1. A method of manufacturing a semiconductor device, comprising: a step of bonding main constituent atoms of a semiconductor substrate with ion-implanted atoms.