JP3057712B2 - Method for manufacturing crystalline silicon substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention uses a chemical vapor deposition method on a glass substrate,
The present invention relates to a crystalline silicon substrate on which a crystalline silicon thin film is formed, and more particularly, to a crystalline silicon substrate used for manufacturing a thin film transistor array used for a liquid crystal television, a projection television, a printer, an image scanner, and the like, and a method for producing the same. .

[Conventional technology and its problems]

Chemical vapor deposition methods include atmospheric pressure chemical vapor deposition, reduced pressure chemical vapor deposition (hereinafter referred to as low pressure CVD), plasma chemical vapor deposition (hereinafter referred to as plasma CVD), and the like. In order to form a crystalline silicon thin film such as a polycrystalline silicon thin film or a microcrystalline silicon thin film on a glass substrate, for example, a method in which a substrate temperature is set to about 500 to 700 ° C. by using a low pressure CVD method is used. Also, plasma CV
There is known a method in which a raw material containing silicon atoms such as silane (SiH ₄ ) is highly diluted with a diluent gas such as hydrogen using the D method, and a film is formed with a high input power.

However, each has a small crystal grain size and, for example, has a field effect mobility of 100 c when used as a semiconductor of a thin film transistor.
It was difficult to fabricate a transistor having m ² / V · S or more.

Therefore, using solid phase growth or performing laser annealing,
The crystal grain size of the crystalline silicon thin film is enlarged to improve the characteristics of the transistor. However, solid phase growth requires a high temperature of 500 to 700 ° C and requires a long firing time of 10 to 20 hours, and laser annealing also requires a long time treatment. There are many problems.

[Means for solving the problem]

In the present invention, a resist is applied to one surface of a glass substrate, and after patterning the shape of the small holes, the glass substrate is etched to form small holes uniformly, and silicon single crystal fine particles are formed only in the small holes. This is performed by a method of manufacturing a crystalline silicon substrate by forming a crystalline silicon thin film on a surface where silicon single crystal fine particles are distributed in small holes by a chemical vapor deposition method.

Further, when the glow discharge method is used in the chemical vapor deposition method, the decomposition of the raw material and the surface reaction are promoted by the plasma, and the crystallization of the crystalline silicon thin film is promoted.

[Action]

Although the mechanism of the present invention is not clear, the silicon single crystal fine particles in the small holes on the glass substrate serve as nuclei for the crystal growth of the silicon thin film deposited on the glass substrate by the chemical vapor deposition method. Is considered to be relatively easy to form.

Also, by forming the small holes, it becomes possible to uniformly distribute the silicon single crystal fine particles on the glass substrate,
Crystal grains of the formed silicon crystal thin film can be made uniform.

Embodiment 1 Hereinafter, the present invention will be described in detail with reference to the drawings.

A photosensitive resist is applied onto a glass substrate 1 (Corning 7059 low-expansion glass Corning), and a mask is exposed.
After development, small holes of about 0.01 to 1.0 μm were patterned. Note that the resist used for patterning may be an electron beam resist.

Thereafter, the small holes 5 were formed in the glass substrate by etching the glass with an etching solution of hydrofluoric acid. The pores are evenly distributed on the glass substrate, and the distance between the pores is 1.0
It was formed into a lattice shape at 5.05.0 μm. In addition, the depth of the small hole is 0.1 to
1.0 μm.

Next, a 0.01-1.0 μm
The silicon single crystal fine particles 2 were dispersed, and then the glass substrate was wiped off with a cloth to leave the silicon single crystal fine particles only in the small holes, thereby uniformly dispersing the silicon single crystal fine particles (see FIG. 1). .

Next, low power density (0.1-0.3W / cm ² ) using glow discharge by plasma CVD method with SiH ₄ and H ₂ as source gas
In the _{H 2 / SiH 4 = 8 /} 1~10 / 1 dilution ratio, 200-4 substrate temperature
When a silicon thin film is deposited at 00 ° C, the particle size is 100 to 500.
A crystalline silicon substrate having a crystalline silicon thin film of about Å can be obtained (see FIG. 2).

The field effect mobility of the thin film transistor using the crystalline silicon substrate manufactured as described above was 100 cm ² / V · S or more, showing good characteristics.

[Example 2] A glass substrate in which silicon single crystal fine particles were uniformly distributed in small holes as in Example 1 was formed using a low-pressure CVD method.
When a silicon thin film was deposited at a substrate temperature of 500 to 600 ° C. using SiH _{4 as a} raw material, a crystalline silicon substrate on which a crystalline silicon thin film having a grain size of 300 to 1000 ° was formed was obtained.

The field effect mobility of the thin film transistor using the crystalline silicon substrate manufactured as described above was 100 cm ² / V · S or more, showing good characteristics.

〔The invention's effect〕

As described above, the present invention forms small holes on a glass substrate, distributes silicon single crystal fine particles only in the small holes, and then deposits a silicon thin film by chemical vapor deposition. In addition, a crystalline silicon thin film having a large particle size can be formed relatively easily at a low temperature, and a complicated and long process such as conventional solid phase growth and laser annealing can be omitted.

Using a crystalline silicon substrate on which a crystalline silicon thin film having a large particle size is formed, a crystalline silicon thin film transistor array having excellent transistor characteristics can be formed, and a large area thin film can be formed. This makes it easier to manufacture active matrix LCDs with a driver and a driving circuit formed at the same time, improving factory productivity and reducing product costs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a glass substrate in which silicon single crystal fine particles are distributed in small holes, and FIG. 2 is a cross-sectional view showing one embodiment of a crystalline silicon substrate of the present invention. DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Silicon single crystal fine particle 3 ... Crystal silicon substrate 4 ... Crystal silicon thin film 5 ... Small hole

Claims (2)

(57) [Claims] 1. A method of coating a resist on one surface of a glass substrate, patterning the shape of the small holes, etching the glass substrate to uniformly form small holes, and forming silicon single crystal fine particles only in the small holes. And then forming a crystalline silicon thin film on the surface where the silicon single crystal fine particles are distributed in the small holes by a chemical vapor deposition method. 2. The method according to claim 1, wherein a glow discharge is used in the chemical vapor deposition method.