JPH036015A - Semiconductor film - Google Patents

Abstract

PURPOSE:To reduce an irregularity in a characteristic at each product by a method wherein a crystal particle size is controlled within a specific range and a hydrogen treatment is executed so as to reduce an irregularity in the particle size and to set a hydrogen content to a specific range. CONSTITUTION:An insulating substrate 1 is formed in a flat-board shape having a comparatively large size; a thin film 2 composed of silicon is applied to and formed on its upper surface. The thin film 2 is formed by applying a glow discharge method, a CVD method, an electron-beam vapor deposition or the Iike; the insulating substrate 1 where this thin film 2 has been applied and formed is placed on a support body 3. During this process, the substrate is placed in such a way that the thin film 2 is situated at the lower side and that the thin film 2 comes into contact with the susceptor 3. This semiconductor film is composed of polycrystalline silicon whose hydrogen content is 10<18> to 10<21>atoms/cm<3>, whose crystallization rate is 70 to 100% and whose crystal particle size is 50 to 70Angstrom . Thereby, it is possible to obtain the semiconductor film whose irregularity as a product is small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor film. More specifically, the present invention relates to a semiconductor film useful as a semiconductor layer of a thin film semiconductor.

This semiconductor is applied to optical sensors and various types of IC1 displays.

[Prior art]

Conventionally, in order to fully bring out the characteristics of Si in a semiconductor film, it has been necessary to form Si in a single-crystalline or polycrystalline state and to reduce the defect density inside and outside the crystal. As a countermeasure, amorphous Si, polycrystalline Si
However, in this method, the laser annealing spot diameter is scanned with a diameter of about 200 to 300 μm, so the annealing time inevitably becomes longer. For example, in the case of a 4-inch wafer, it takes about 1 hour. This seriously impedes productivity improvement.

Further, grain boundaries are generated as a result of the recrystallization, and these grain boundaries reduce the current instantaneous ability, particularly in the channel portion of the MOS Tr, and as a result, increase variations in product characteristics.

〔the purpose〕

The purpose of the present invention is to make the number of grain boundaries in the channel part of a Tr, especially a MOSTr, as constant as possible for each product;
Furthermore, the aim is to make the current opening ability in the channel part as uniform as possible.

〔composition〕

As a result of intensive research to achieve the above object, the inventors of the present invention have found that lamp annealing can make the number of grain boundaries relatively constant, and that this can be used to create semiconductor films that satisfy specific conditions. It was discovered that by forming a semiconductor film, it is possible to obtain a semiconductor film with less variation as a product.

That is, the semiconductor film of the present invention has (a) hydrogen-containing i1018-1018 atoms/cm3
(b) Crystallization rate of 70-100% (c) It is characterized by being made of polycrystalline silicone with a crystal grain size of 50-70%.

In the present invention, when hydrogen is not added to the semiconductor film, S
Dangling bonds in i cannot be terminated, causing carrier trapping.

Limiting the crystallization rate is to improve carrier mobility, and limiting the crystal grain size contributes to preventing variations in product characteristics.

The present invention will be specifically explained using FIGS. 1 to 3. The insulating substrate 1 has a flat plate shape with relatively large dimensions, and has a thin film 2 made of silicon deposited on its upper surface. In this case, for example, a glow discharge method (PVC method), a CVD method, or an electron beam evaporation method is applied to form a thin film 2.
is formed. The insulating substrate 1 with the thin film 2 formed thereon is placed on the support 3. In this case, the thin film 2 is placed so as to be in contact with the support 3 with the thin film 2 facing downward. As support 3 a single crystal silicon (LIL) wafer is used. Then, the entire area is simultaneously irradiated with light using a tungsten halogen lamp 4 located above the thin film 2 and connected to a power source 5. In this case, the insulating substrate is made of a material that is transparent to the light emitted from the lamp 4, such as transparent quartz.

Since single-crystal silicon has strong light absorption characteristics for the irradiated light from the tungsten halogen lamp 4,
The support 3 made of monocrystalline silicon is first heated, and the heat is transferred to the thin film 2 by thermal conduction, as indicated by arrow A in FIG. Then, recrystallization of the thin film 2 starts from the interface between the support 3 and the thin film 2.

When the single crystal silicon 2' is formed at the interface in this manner, the single crystal silicon 2' itself absorbs the irradiated light and self-heats, so that the thin film 2 is uniformly heated.

As a result, the particle size can be made uniform and the particle size can be easily controlled, so that the semiconductor film of the present invention can be easily manufactured.

Example A thin film 2 made of amorphous silicon was heated with RF power (20W).
), gas flow rate 20 SCCM, 5il14 (100%)
, a thickness of 0.05 to 0.5 μm under conditions of a pressure of 0.1 Torr and a substrate temperature of 220° C. In this case, transparent quartz having a thickness of 0.05 to 4.0 mm is used as the insulating substrate. The silicon wafer as support 3 has a diameter of 6 inches, crystal orientation (111) P type, and a thickness of 0.4
~0.6mm.

The lamp annealing device used had a tungsten halogen lamp, and the heating characteristics were as shown in Figure 4, with a heating temperature of 750 to 900°C and a heating time of 30 to 1000°C.
Seconds.

Annealing is N2. It is carried out in an inert gas such as Ar or Ne.

Hydrogenation was performed under H2 atmosphere with RF power (18KW),
The processing time was 60 minutes.

The upper line in Figure 5 is a characteristic curve showing the peak value of Raman spectroscopy, and the vertical axis a corresponds to this, and this vertical axis a shows the peak position N (am-1) of the waveform by Raman spectroscopy. . The lower line in Figure 5 is a characteristic curve showing the crystal grain size, and the vertical axis corresponds to this.
(Transmission electron microscope) Shows the crystal grain size (in) that protrudes.

As is clear from Figure 5, the crystal grains of the polycrystalline Si film grow as the annealing time increases (annealing temperature: 800°C), and in 120 seconds they have grown to approximately the desired grain size of 60mm crystals. .

When the annealing temperature is 900°C, almost the objective can be achieved in 30 seconds.

〔effect〕

In the present invention, the crystal grain size is controlled to 50 to 70 people,
The spin density is compensated because the particle size variation is small and the hydrogen treatment is performed so that the hydrogen content falls within a specific range.

As a result, the semiconductor film of the present invention can be used as a normal thin film semiconductor (T
When used as PT), the variation in characteristics from product to product is extremely small (Fig. 6). On the other hand, since the particle size of the conventional type varies from 2000 to 3 μm, the characteristics inevitably vary greatly from product to product (Fig. 7).

In addition, when this semiconductor film is used as a semiconductor layer of MO5Tr, it exhibits a specific resistance of 100 to 1, and 1xlO-G to 1xlO-'(00m)-1 when irradiated with light of 0OOQux, making it useful as an optical sensor. It is.

[Brief explanation of drawings]

FIG. 1 shows a lamp annealing apparatus used for manufacturing the semiconductor film of the present invention, FIG. 2 is a cross-sectional view thereof, and FIGS. 3(a) to (c).
) is a cross-sectional view showing the recrystallization process. FIG. 4 shows the heating characteristics of the device. FIG. 5 shows an investigation of the annealing time dependence of Raman spectroscopy and TEM characteristics during annealing at 800° C. under N2. FIG. 6 shows a TPT according to the present invention.
Figure 7 shows the variations in the characteristics of the conventional TPT. 1... Insulating substrate 2... Thin crotch 2'...
Single crystal silicon 3...Support 4°゛°tungsten halogen lamp 5...Power source Figure 1 Td: Anneal S section ↑d Near anneal 8 Terama Rh'J! 3'! ' Fig. 2 Anneal Time Bullet 7

Claims (1)

[Claims] 1. (a) Hydrogen content 10^1^8 to 10^2^1at
om/cm^3, (b) crystallization rate of 70 to 100%, and (c) crystal grain size of 50 to 70 Å.