JPS61234534A - Fabrication of silicon nitride coating - Google Patents

Abstract

PURPOSE:To form a film without sputtering a fundamental substrate on which a coating is formed and without damaging the foundation by applying the electric energy or light energy to the mixture of a nitride gas selected out of nitrogen, ammonia and hydrazine and a compound composed of silicon, nitrogen, and hydrogen atoms comprising N-H connection, Si-H connection, and N-Si connection respectively. CONSTITUTION:The electric energy, light energy or the energy corresponding them is applied to a compound composed of silicon, nitrogen and hydrogen atoms comprising at least one of N-H connection, Si-H connection, and N-Si connection respectively, for example, silazane H3Si[NHSiH2]mNHSiH3(m>=0) and silylamine (H-Si)nNH3-n(n=1-3), and a reactive mixture of nitride selected out of nitrogen (N2), ammonia (NH3), and hydrazine (N2H4), thereby forming a silicon nitride coating. Consequently, formation of the coating becomes possible at the lower temperature 100-200 deg.C, for example, 150 deg.C and the damage of the fundamental substrate or the inclusion of impurity form the fundamental substrate can be removed.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a method for producing a silicon nitride non-single crystal semiconductor film that can be applied to various semiconductor devices such as photoelectric conversion semiconductor devices, non-linear elements, and LSIs. It is.

"Prior Art" Conventionally, methods for producing silicon nitride semiconductors used in photoelectric conversion semiconductor devices and semiconductor devices with nonlinear characteristics include a plasma vapor phase reaction method using a glow discharge method or a mercury (h) aggravation method. Silane (
SiH4) and ammonia (Nnz) are reacted, and 20
A film was formed on a substrate maintained at 0 to 400°C. In addition, other reactive gases include polysilanes such as disilane,
Nitrogen (N2), hydrazine (Nzlln), etc. were used.

``Problems to be Solved by the Invention'' However, these conventional silicon nitride production methods are designed to minimize impurity contamination from or into the base substrate in the plasma vapor phase method, and to produce silicon nitride semiconductors with good film quality. In order to obtain this, it is necessary to form a film at low output, resulting in a problem that the film forming speed is very slow. In addition, the photovapor phase reaction method has relatively few problems like the plasma vapor phase method, but the film formation rate is very slow, and it was necessary to use mercury (Hg), which is harmful to the human body, to increase the film formation speed. .

"Means for Solving the Problems" The present invention provides compounds consisting of silicon, nitrogen, and hydrogen atoms having at least one N-H bond, one Si-H bond, and one or more N-Si bonds, such as silazane H, Si (NH
SiH,) mNHSiH3 (m≧0), silylamine (H-3i), INH3-fi (n = 1-3)
A method of creating a silicon nitride film by applying electric energy, light energy, or equivalent energy to a reactive mixture of nitrides selected from nitrogen (N2), ammonia (NH3), and hydrazine (N2H4). be.

"Function" According to the method of the present invention, a film can be formed at a low temperature of 100 to 200°C, for example, 150°C, and damage to the underlying substrate or contamination of impurities from the underlying substrate can be removed. Furthermore, it is effective as a P- or N-type silicon nitride film and as a P- or N-type semiconductor with a wide energy band width for photoelectric conversion devices.

Embodiments of the present invention will be described below with reference to the drawings.

"Example 1" In this example, nitrogen, silicon, trisilylamine ((H3si)J) was used as the hydrogen compound, and ammonia (NH3) was used as the nitride. The production method was a photo-vapor phase reaction method (photo-CVD method). FIG. 2 shows a schematic diagram of the apparatus used in this example.

In FIG. 2, a substrate (5) is arranged on and in contact with a heater (4) and a heater cover (7). Gas line (9)
Trisilylamine was introduced into the reaction chamber (3) from the gas line (10) with ammonia at a flow rate ratio (HzSi) of 3N/NH3 = 1/1, and the conductance valve (14)
The pressure inside the reaction chamber was set at 52 Hrr. At this time, the substrate (5) is maintained at 200° C. by the heater (4).

Furthermore, ultraviolet light of 300 nm+ or less including light with a wavelength of 184 nm was irradiated with a low-pressure mercury lamp (6) to cause a photochemical reaction and form a silicon nitride film on the substrate. The light source section (6) for photochemical reactions is made to have exactly the same pressure as the reaction chamber by the valve (13), and the absorption of large active gases such as Nz+He and other inert gases and light with wavelengths in the ultraviolet region is kept as low as possible by the valve (12). I suppressed it. Further, as a result of forming a film in the same manner by changing the number or type of low-pressure mercury lamps (6), a relationship as shown by straight line 1 in FIG. 1 was obtained.

For comparison, ammonia (NH3) was supplied through the gas line (11) at a flow rate of N using the same reactor.
Straight line 2 in FIG. 1 shows the results of a similar experiment conducted with H3/Siz)L = 5/1 introduced into the reaction chamber.

At this time, the CV characteristics of the silicon nitride film with a thickness of approximately 2000 mm obtained by the method of the present invention were measured, and the obtained interface states were extremely small at 1.2 x 10"cm-", and the refractive index was = 2.0, the film quality was very good.

"Example 2" In this example, as in Example 1, trisilylamine was used, hydrazine (NJ4) was used as the nitride,
It was formed using a known plasma CVD apparatus. The flow ratio of both substances (H3Si): +N/NzH4 = 1/1,
Reaction chamber pressure 0.12Hrr, substrate temperature 300℃, RF
A silicon nitride film was formed with a power of 10 mw/cm". As a result, the refractive index was 1.95. The interface unit obtained from the CV characteristics was 2.5 x 10" cm, which was created using the conventional plasma CVD method. The value was extremely low compared to the membranes prepared.

"Effects" Since the present invention uses a compound having a 5t-N bond from the beginning as a starting material, less energy is required to decompose the reactive mixture and form a film. Therefore, the film could be formed without sputtering the base substrate on which the film was to be formed (without damaging the base).

Furthermore, when the method of the present invention is applied to semiconductor devices (for example, solar cells, non-linear elements, LSI), etc., it is possible to reduce the amount of impurities mixed in from the lower layers and to minimize damage to the lower layers. Good characteristics were obtained.

In addition, photovapor phase reactions allow film formation at lower temperatures than conventional methods, making it possible to form films using compound semiconductors (e.g. InP).
It can be used as a file passivation film for semiconductor devices that cannot be maintained at high temperatures.

[Brief explanation of drawings]

FIG. 1 shows the relationship between the deposition rate and applied energy of a film formed by the method of the present invention. FIG. 2 schematically shows the optical CVD apparatus used in the present invention.

Claims (1)

[Claims] 1. A compound consisting of silicon, nitrogen, and hydrogen atoms each having at least one N-H bond, one Si-H bond, and one or more N-Si bonds, nitrogen (N_2), ammonia (NH_3
), hydrazine (N_2H_4), and a mixture thereof with a nitride gas selected from hydrazine (N_2H_4). 2. In claim 1, the compound consisting of silicon, nitrogen, and hydrogen atoms is H_3Si[NHSiH_2]_mNHSiH_3(m
≧0) (H-Si)_nNH_3_-_n (n=1~3
) A method for producing a silicon nitride film, characterized in that it is made of dilazan and silylamine.