JPS6138269B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a so-called photovapor phase chemical growth method, in which a film of a substance generated by a photochemical reaction is grown on the surface of a substrate from a gas phase, and mainly relates to the photovapor phase chemical growth (hereinafter referred to as photoCVD) process for forming a Si ₃ N ₄ film. Targeting equipment. In manufacturing semiconductor devices such as transistors and ICs, vapor phase chemical reaction methods are used to form chambered films such as Si ₃ N ₄ films, oxide films such as SiO ₂ films, or amorphous Si films on semiconductor substrates. However, the conventional method is to directly heat the semiconductor substrate in a furnace in order to advance the chemical reaction, that is, to thermally decompose the substance to be reacted in the gas phase using thermal energy, and at the same time The film was grown on the substrate. As the above-mentioned heating means, methods such as infrared lamps, high frequency heating, or electric resistance heating have been used. However, such a method in which heating is the main condition for the chemical reaction is carried out at a considerably high temperature, making it unsuitable for film formation on a substrate having a material portion with a low melting point. By the way, according to Japanese Patent Publication No. 39-2426, in a method of forming a single crystal semiconductor layer on a semiconductor substrate by the epitaxial method, which is one of the vapor phase chemical growth methods in a broad sense, the semiconductor substrate is heated with a heating element. However, it is described that the reaction can be accelerated even at temperatures as low as 300°C by exposing the reactant to ultraviolet light. When forming a Si ₃ N ₄ film on a Si semiconductor substrate, the conventional CVD method, for example, a method in which monosilane (SiM ₄ ) and ammonia (NH ₃ ) are reacted,
Although it can be formed at a relatively low temperature of 600°C, when forming a Si ₃ N ₄ film on a semi-dynamic device such as a transistor or IC, it is necessary to perform ultraviolet irradiation and lower the temperature to about 100 to 300°C. However, if this photo-vapor phase chemical reaction is carried out, for example, by placing a sample in a quartz tube and irradiating light from the surface of the quartz tube while passing the reaction gas through the tube, a CVD film will adhere to the inner wall of the quartz tube.
The drawback was that light was blocked from reaching the reactant gas. Therefore, the present invention has been devised so that the decomposition growth effect can be performed without reducing the light energy even during the formation of the CVD Si ₃ N ₄ film described above. Therefore, an object of the present invention is to provide a method for stably forming a photochemically grown film. The basic method for achieving the above purpose is to transmit the light that has passed through the light transmission window through the gas nozzle,
By configuring the sample surface to be irradiated with the light, an active gas reaction is caused to occur on the sample surface,
It is characterized by eliminating film adhesion to the light-transmitting window. Hereinafter, a detailed description will be given along with examples. In the drawing, an apparatus for photovapor phase chemical growth according to the invention is shown, 1 denotes a xenon-mercury (Xe
-Hg) lamp, 2 is a quartz jig that can also be a light transmission window and a nozzle, 3 is a supply port for _N2 gas to act as a gas curtain and carrier gas, 4 is a supply port for _SiH4 gas, 5 is the NH ₃ gas supply port. 6 is a Si wafer, placed on a support stand 7, and heated by a heat block 8 of 100
Heated from ℃ to 300℃. The light emitted from light source 1 is
By passing through the gas body in the nozzle through the window of the quartz jig 2 and irradiating the surface of the Si wafer, the light irradiates SiH ₄ gas and NH ₃ gas,

The reaction in [Table] generates active ・SiH ₃ gas and ・NH ₂ gas, and these gases can be applied to the Si wafer surface without forming a film on the window of the quartz jig or inside the quartz nozzle. 3.SiH ₃ +4.NH ₃ +12.Hhν/100° C. Si ₃ N ₄ +12H ₂ A Si ₃ N ₄ film is deposited by the reaction ↑. By introducing SiH ₄ gas and O ₂ gas instead of the above gases and performing light irradiation in the same manner, a SiO ₂ film is formed on the surface of the Si wafer. According to the present invention as described in the above embodiments, the objectives can be achieved as follows. The ultraviolet rays from the Xe-Hg lamp activate and pass through the individual gases in the quartz jig, further promoting the photochemical reaction on the Si wafer surface, and at the same time promoting the photochemical reaction to the gas body within the quartz jig. The light irradiation does not cause any film to adhere to the window of the quartz jig, so the film may not adhere to the window, resulting in a decrease in light transmission and, in turn, activation of the gas and reduction in photochemical reactions. Photo-CVD reactions can be carried out without causing any damage. As described above, the present invention includes a light source, a jig having a light transmitting window that transmits light from the light source, and a nozzle that generates an inert gas or a deposition gas, a support stand that supports a wafer on which the deposition gas is deposited, and It consists of a heat block that heats the support table, and the light emitted from the light source passes through the light transmission window and irradiates the gas body in the nozzle, and also irradiates the wafer surface, so that the active gas reaction can be stimulated. This has the effect of providing a photochemical reaction device that can be carried out on the wafer surface and eliminate the need for a film to adhere to the light transmission window.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a photochemical reaction device showing one embodiment of the present invention. 1...Xe-Hg lamp, 2...quartz jig, 3,
4, 5...Gas supply port, 6...Sample, 7...Support, 8...Heater.

Claims (1)

[Claims] 1. A light source, a jig having a light transmitting window that transmits light from the light source, and a nozzle that generates an inert gas or a deposition gas, a support stand that supports a wafer on which the deposition gas is deposited, and a heat source that heats the support stand. 1. A photochemical reaction device comprising a block, wherein light emitted from a light source passes through the light transmission window and irradiates a gas body within a nozzle, and is also irradiated onto a wafer surface.