JPS6017911A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a uniform single-crystal layer over a whole semiconductor layer by providing a film which reflects infrared rays or visual light rays on an insulator beneath the semiconductor layer. CONSTITUTION:A nitride film 4 is deposited on an insulating substrate 1 and a resist 6 is applied on the film 4 along the peripheral part of a domain in which an island shape semiconductor layer is to be formed. When the resist 6 is removed after etching, the nitride film 4 remains along the peripheral part of the island shape semiconductor layer. Polycrystalline silicon is deposited to form the island shape semiconductor layer. A laser beam is applied to the island shape polycrystalline silicon layer 2 along the longer side direction. Because the nitride film has a larger refractive index than an oxide film, it reflects thermal rays (infrared rays and visual light rays) from smelted silicon layer so that the heat is not discharged from the polycrystalline silicon layer 2. Therefore, the silicon of the peripheral part of the semiconductor layer is kept at higher temperature than that of the center part and the growth from random nuclei is suppressed so that the whole island of the semiconductor layer is single-crystallized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a semiconductor single crystal film on an insulator.

Conventionally, with regard to the manufacturing method of this type of semiconductor device, there has been no attempt to manufacture so-called two-dimensional circuit elements in which many semiconductor active layers are laminated in order to increase the speed and density of semiconductor devices. Semiconductor single crystal? A method of forming it is being considered. The method of forming a semiconductor single crystal on this dielectric is to deposit a polycrystalline or amorphous semiconductor on an insulator, and then irradiate the surface with energy beams such as laser light or electron beams, so that only the surface layer can be formed. heat the
There was a method of melting to form a single crystal semiconductor film.

Next, as shown in Figure 1 (C), oxidize at 950°C to form an oxide film (3), and then oxidize at a reduced pressure of C.
A nitride film (4) is entirely deposited by the VD method, and patterned by photolithography. After further exposure to a 950C oxidation atmosphere for a long time, the patterned nitride film (4) and oxide film (3) are removed, as shown in Figure 1(d).
As shown in FIG. 1, a polycrystalline or amorphous semiconductor, in this case polysilicon, is formed on a substrate (1). (5)
is an oxidized polysilicon layer.

FIG. 1(e) shows a plan view of No. 11m1(d). Next, the island-shaped polysilicon layer (2) shown in FIG.
A laser beam narrowed to a spot about twice to twice as large is irradiated while scanning in the longitudinal direction of the pattern. At this time, the polysilicon layer (2) is melted, solidified after irradiation, and simultaneously recrystallized. Furthermore, M O is added to this polysilicon recrystallized layer.
S) Form the resistor using known prosene.

However, in this conventional method, the intensity distribution of the laser beam used is a so-called Gaussian distribution in which the intensity is strong in the center and weak in the periphery, so the temperature distribution of the irradiated polysilicon island is high in the center and low in the bottom. By providing a reflective film for infrared or visible light in contact with the insulator,
Provided is a novel method for manufacturing a semiconductor device that can form a uniform single crystal layer over the entire semiconductor layer even with a Gaussian distribution laser beam, etc., since heat is difficult to escape in the peripheral area of the semiconductor layer. It is something to do.

Hereinafter, one embodiment of the present invention will be described based on the drawings. In FIG. 2 4a), (1) is a quartz substrate (Jot) that is to be a substrate. As shown in Figure 2(b), the nitride film (
(Si, N,) (4) 100 OA of gold is deposited and a resist (5) is applied to a portion corresponding to the periphery of the region where an island-shaped semiconductor layer is to be formed in the future. Next, a portion below the peripheral portion of the semiconductor layer is etched using a reactive ion etching method. After that, when the resist (6) is removed,
As shown in FIG. 2(c), the nitride film (4) remains only in a portion corresponding to the peripheral portion of the island-shaped semiconductor layer. Thereafter, as in the conventional method, polysilicon was deposited to form an island-shaped semiconductor layer, as shown in FIG. 2(d). FIG. 2(e) shows a plan view of the second [9(d)]. Thereafter, the laser beam is prevented from escaping from the long contact layer of the island-shaped polysilicon layer. Therefore, the silicon at the periphery of the semiconductor layer is kept at a higher temperature than at the center. Therefore, since assimilation occurs from the center toward the periphery, growth from random nuclei is suppressed and the entire semiconductor layer island becomes a single crystal.

In the above embodiment, the interface between different types of insulators was used as the reflective film, but as shown in Fig. 8, a thin metal film (Mo), tungsten (T), etc.
Even if 7) is provided, or even if it is embedded in an insulator as shown in FIG. 4, the effect shown in (b) can be obtained.

As described above, this invention forms a reflective film against heat rays in contact with the insulator below the periphery of the semiconductor layer, making it difficult for heat to escape from the periphery of the semiconductor layer, resulting in uniform single crystal formation throughout the semiconductor layer. The semiconductor layer can be gold-tin.

[Brief explanation of drawings]

1(a) to 1(d) are cross-sectional views showing a conventional method of manufacturing a semiconductor device, FIG. 1(e) is a plan view of FIG. 1(d), and FIG. 2(a). ' (d) is a cross-sectional view showing one embodiment of the present invention, No. 2 (e) is a plan view of FIG.
In the figure and No. 4 (2), (1) is an insulator (or quartz), (2) is a polysilicon layer, (3) is an oxide film, (4) is a nitride film, and (5) is a polysilicon layer. oxide film,
(6) is a resist, and (7) is a metal film. Applicant Hirobe Kawada, Director of the Agency of Industrial Science and Technology, Figure 1, Figure 2, Ward 3, 51-7

Claims (1)

[Claims] (1) A polycrystalline or amorphous semiconductor layer surrounded by an insulator is formed on an insulator, and a laser beam or an electron beam is irradiated to the center of the semiconductor layer to form the semiconductor layer. Method of crystallizing mold manufacturing method.