JPH02130912A - Thin film semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a thin film semiconductor device whose operating speed is high by forming a semiconductor layer constituted of a two-layer structure of an amorphous semiconductor layer and a polycrystalline semiconductor layer on a glass substrate, and forming a semiconductor device on said two-layer structure semiconductor layer. CONSTITUTION:An amorphous Si layer 2 is formed on the surface of a glass substrate 1 by CVD method or sputtering method; the surface of the layer 2 is irradiated with far ultraviolet rays or far ultraviolet ray laser light or low acceleration electron beam by using scanning method or collective irradiation method; thereby forming a polycrystalline Si layer 3. In this layer 3, an MOSFET composed of a gate insulating film 4, a gate electrode 5 and an interlayer insulating film 6 is formed as a source 7, a drain 8 and a gate 9. Thereby, a thin film semiconductor device whose operating speed is high can be formed.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to a semiconductor thin film structure of a thin film semiconductor device.

[Conventional technology]

Conventional thin film semiconductor devices include thin film semiconductor devices in which a polycrystalline Si film is formed on a quartz substrate and a semiconductor device is formed on the polycrystalline Si, and an amorphous Si film is formed on a Corning #7059 glass substrate and the amorphous There has been a thin film semiconductor device in which a semiconductor device is formed in a Si film.

[Problem to be solved by the invention 1 However, according to the above conventional technology, polycrystalline S on a quartz substrate
Thin film semiconductor devices using i-films have a high operating speed, but there is a problem in that quartz substrates are about an order of magnitude more expensive than glass substrates, and amorphous silicon on glass substrates
Although the cost of a glass substrate for a thin film semiconductor device using a film is low, there is a problem in that the operating speed of the semiconductor device is slow.

It is an object of the present invention to solve the problems of the prior art and to provide a thin film semiconductor device that is inexpensive and operates at high speed.

[Means for Solving the Problems] In order to solve the above problems, the present invention relates to a thin film semiconductor device, in which a semiconductor layer having a two-layer structure of an amorphous semiconductor layer and a polycrystalline semiconductor layer is formed on a glass substrate, Basically, a method is adopted in which a semiconductor device is formed in the two-layer structure semiconductor layer.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows a thin film semiconductor transistor (TFT) showing an embodiment of the present invention.
FIG. i.e. Corning #70
An amorphous Si layer 2 is formed on the surface of a glass substrate 1 made of 59 or the like by a CVD method or a sputtering method, and the surface of the amorphous Si layer 2 is scanned with deep ultraviolet light, far ultraviolet laser light, or a low-acceleration electron beam. irradiation by a method or a batch irradiation method to form a polycrystalline Si layer 3,
A MOSFET (Metal-O
xide-Semic.

ndductor Field EffectTra
The amorphous Si layer according to this example, which is formed of ns i 5 tar) as the lease 7, drain 8, and gate 9, acts as a thermal buffer for the annealed film against light beams and electron beams, and the annealed film on the base glass substrate l. This has the effect of preventing cracks and the like caused by melting and thermal strain. Further, the thickness of the polycrystalline Si layer 3 during annealing can be limited to approximately 900 layers remaining on the surface depending on the wavelength of the light beam and the acceleration energy of the electron beam, and the thickness of the underlying amorphous Si layer 2 can be limited to approximately 900 layers.

Approximately 1,000 people may remain, and the pre-formed amorphous Si layer may be about 2,000 people or less, and the gate insulating film may be formed at a low temperature, such as by CVD or a SiO□ film. Furthermore, since the amorphous Si layer 2 has a function other than thermal buffering and has a resistance value close to that of an insulator, it can also be used for element isolation.

Note that the semiconductor layer is not only a Si layer but also Ge, SiC, Se
It goes without saying that it may be made of other semiconductor materials such as , GaAs, and InP.

[Effects of the Invention] The present invention has the advantage that a thin film semiconductor device that is inexpensive and has a high operating speed can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thin film semiconductor device showing one embodiment of the present invention. 1 ・ ・ ・ 2 ・ ・ ・ 3 ・ ・ 4 ・ ・ ・ 5 ・ ・ 6 ・ ・ 7 ・ ・ ・ 8 ・ ・ ・ 9 ・ ・ ・ Glass substrate Amorphous Si layer Polycrystalline Si layer Gate Insulating film Gate electrode Applicant for eyebrow insulating film lease drain gate and above Seiko Epson Corporation

Claims (1)

[Claims] A thin film semiconductor device characterized in that a semiconductor layer having a two-layer structure of an amorphous semiconductor layer and a polycrystalline semiconductor layer is formed on a glass substrate, and a semiconductor device is formed on the two-layer structure semiconductor layer.