JPH02185019A - Method for manufacturing polycrystalline silicon film with large grain size - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides poly-
The present invention relates to a method for manufacturing an Si film.

[Prior art]

In TPT having Poly-Si as an active layer, the larger the crystal grain size, the higher the mobility. Therefore, if such a TPT is used in a driver circuit for a sensor such as a facsimile machine or a liquid crystal display, it becomes possible to drive the sensor at high speed.

Therefore, P poly with large crystal grain size is placed on an insulating substrate.
- Research and presentations have been made on techniques for forming Si films. Reaction material 54, No. 12. (1985), p. 1274 and 19th Hedron Element Conference (1986) To
ky.

In such cases, a laser or electron beam is used to
A so-called melt recrystallization method for melting and recrystallizing y-Si has been announced, and in Ohritsu, Autumn (1987) Proceedings 19P-Q-9 and 18P-L-2, amorphous silicon A so-called solid phase growth method has been announced in which a film is formed and then crystallized by 7 anneals.

However, when using the melt recrystallization method, it is not possible to uniformly recrystallize a large area, and when using the in-phase growth method, it is difficult to reduce the crystal nucleus density in the amorphous Si film. Methods for creating amorphous Si films include a) low-temperature film formation by LP-CVD method, b) Poly-
Amorphousization of Si film by Si ion implantation, C) vacuum evaporation, etc. are known. In case a), the density of crystal nuclei is the highest, and in case b), P poly before amorphousization is known.
- Reflecting the properties of Si, the surface morphology is poor and vacancies are present in the film, which becomes an obstacle when growing crystals. Therefore, among a), b), and c), C
) is the most preferable because it has a low crystal nucleus density, but the in-phase growth method still has a limit of crystal grain size of about 10 μm.

〔the purpose〕

An object of the present invention is to provide a method for producing a Poly-Si film having a large crystal grain size and capable of producing a uniform and large area.

〔composition〕

The present invention relates to a method for manufacturing a polycrystalline silicon film with a large crystal grain size, which is characterized by performing Si ion beam irradiation while depositing Si atoms on an insulating substrate.

The method for depositing the Si particles is preferably the LP-CVD method or the vacuum evaporation method using electron beam heating, but the method is not limited thereto, and any film forming method can be used. Si-ion beam irradiation is also used during film formation.

The irradiation conditions of the Si ion beam vary depending on the film forming conditions using the LP-CVD method or the vacuum evaporation method, but in the case of constant irradiation, the acceleration energy is 10 KeV or less, which is effective, and the total ion dose is I x 10"
~ I x 10" about 1 oz/cm2, implantation energy 5 to 20 keV, preferably dose I x 10"
~I X 10”1ons/a#, injection energy 5
~15 keV.

The Si ion beam serves to amorphize crystal nuclei generated during the deposition of Si atoms, reduce voids in the film, and improve morphology.

The present invention involves two steps: forming an amorphous Si film with a low crystal nucleus density by depositing Si atoms on an insulating substrate and irradiating it with a Si ion beam, and growing the obtained amorphous Si film in a solid phase. Although it can be carried out in separate steps, the deposition temperature of Si atoms (temperature of the substrate)
When Si ion beam irradiation is performed at a temperature of around 600°C (i.e., 550 to 650°C, preferably 580 to 600°C), formation of an amorphous Si film and crystallization by annealing occur simultaneously, and in the - step Po1y -Si
A membrane can be obtained.

The annealing temperature is around 600℃ (i.e. 550~
650°C, preferably 580-600°C) is optimum.

〔Example〕

Example 1 Amorphous Si was deposited on a quartz substrate by LP-CVD method.
A Si ion beam is irradiated at the same time as the film is formed.

The film forming conditions of the LP-CVD method are a temperature of 540°C and a pressure of 0.
3torr, SiH4150SCCM film thickness 1000
The film forming rate is about 0.5 people/see.

The Si ion beam irradiation conditions are acceleration energy 5 eV.
The film surface was scanned at the same time as the film formation started, and 5
Adjust the beam so that the dose is 10"1 ons/c+s".

The amorphous Si film obtained through the above steps was heated to 600°C.
Annealing was performed in an N2 atmosphere for 10 hours.

Table 1 shows the crystal grain size depending on the presence or absence of a Si ion beam. It is clear that the grain size increases due to beam irradiation.

Table 1 Example 2 An amorphous Si film is formed on a quartz substrate by vacuum evaporation and simultaneously irradiated with a Si ion beam.

The film forming conditions for the vacuum evaporation method are a substrate temperature of 400°C and a pressure of IX.
10-' torr, and Si is heated by electron beam heating.
is vapor-deposited. The thickness of the amorphous Si film is 10
00 people, and the film forming speed was 4 people/sec.

Irradiation with the Si ion beam was performed at the same time as the start of film formation.
I x 10”1ons/a with KeV acceleration energy
m” as the total dose.

Table 2 shows the crystal grain size with and without ion beam irradiation after annealing at 600° C. for 50 hours.

It will be done.

It was confirmed that the particle size increased due to beam irradiation, and the mobility of the manufactured TPT could be improved.

Table 2

Claims (1)

[Claims] 1. A method for manufacturing a polycrystalline silicon (hereinafter referred to as Poly-Si) film with a large crystal grain size, which is characterized by depositing Si atoms on an insulating substrate and irradiating it with a Si ion beam.