JPS6150148B2 - - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD This invention relates to chemical vapor deposition equipment.

Recently, research has been conducted into methods for forming relatively large-area amorphous silicon vapor deposition films for use in the production of photosensitive drums for electronic copying machines and solar cells. On the other hand, vapor deposition methods have been studied for forming insulating films and protective films, as disclosed in, for example, Japanese Patent Application Laid-Open No. 163792/1983, and various vapor deposition methods have been proposed depending on the application.

Among vapor deposition methods, this application is particularly concerned with chemical vapor deposition methods that utilize photochemical reactions, and this method has advantages such as extremely fast film formation speed and suitability for vapor deposition over large areas. However, it has been attracting particular attention recently.

Conventional chemical vapor deposition methods using photochemical reactions are
As shown in the above publication, a substrate is placed in a container that transmits ultraviolet rays well, a photoreactive gas is passed through it, and the gas is subjected to a photochemical reaction using an ultraviolet lamp from outside the container, and the reaction products are produced. This method is vapor-deposited onto a substrate, and as mentioned above, it has the advantages of a high film formation rate and can be used on large-area substrates, but the reaction product is also deposited on the inner wall of the container, and UV It was found that there is a drawback in that it greatly inhibits the permeation of

In actual deposition film formation work, it is not possible to wash the inner wall of the container so often, and for this reason,
Specialized containers or reaction devices are also being actively researched, but they are quite complex and difficult to handle.

The present invention has been made in view of the above circumstances, and aims to provide a novel chemical vapor deposition apparatus, which is characterized by: a discharge space that generates stimulating light that causes a photochemical reaction; and a discharge space that receives the stimulating light. a protective gas supply mechanism that surrounds a passage space for a photochemical reaction gas involved in a photochemical reaction in the same container, arranges a discharge electrode toward the discharge space, and supplies the electrode protection gas around the electrode; It is in the place where it is established.

An embodiment of the apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram of the embodiment device viewed from the direction in which the substrate 1 moves, and FIG. 2 is a schematic explanatory diagram of the same device viewed from the direction perpendicular to the direction in which the substrate 1 moves. FIG. 3 is an explanatory diagram of an example of a method of attaching the electrode 2 to the container 3, in which 4 is a discharge space and 5 is a passage space, through which stimulation light emitted from the gas discharge in the discharge space 4 passes. The inner space 6 is surrounded by one container 3. This container 3
For example, as shown in FIG. 3, the electrode 2 and the protective gas supply mechanism, such as the gas pipe 7, are attached to a bowl-shaped glass container 8, and the glass container 8 is inserted into the hole 3a formed in the container 3. Weld together to form a seal. Furthermore, the container 3 is divided into two parts at the position of the arrow Z in FIG. You can also apply it. The material may be quartz glass. In short,
The discharge space 4 and the passage space 5 are connected by a communication space 6 and surrounded by one container 3 without any obstruction. Reference numeral 9 denotes a heater provided as necessary, such as a surface light source unit equipped with a large number of infrared lamps.

In an example of vapor deposition using the above device, the passage space 5
The composition of the photochemical reaction gas G flowing through is a mixed gas of 5 mmHg of argon as a carrier gas, 3 x 10 ^-3 mmHg of mercury as a photosensitizer, and 0.3 mmHg of silicon tetrahydride as a gas for decomposition deposition, and the temperature of the substrate 1 is approximately 150°C. Alumina plate heated to , electrode protection gas g is 8mm
This gas is a mixture of argon (Hg) and mercury (2×10 ^-3 mmHg), and this gas (g) is also used as a discharge gas.
When a discharge is generated in the discharge space 4 with a voltage of 100 V and a current of 8 A, silicon tetrahydride is photodecomposed by the light emitted from the argon and mercury discharge, and amorphous silicon is deposited on the alumina plate. A deposited layer with a thickness of 0.3 μm is formed in approximately 10 minutes.

What is important here is to provide a protective gas supply mechanism for supplying electrode protective gas around the electrode. Naturally, since there is no transparent wall separating the discharge space 4 and the passage space 5 in the communication space 6,
There is no drawback that the silicon produced as a result of photodecomposition is deposited and clouds the transparent wall and blocks the emitted light, but instead, the photodecomposition reaction products diffuse through the communication space 6 and reach the electrodes. As a result, discharge is less likely to occur. To be more specific, when it comes to making discharge easier to occur, electrodes are generally designed and manufactured to have good electron emission. (Ba・
When Sr・Ca)O is coated and the deposition process is repeated using an apparatus without protective gas, various products generated as a result of photochemical reactions gradually adhere to the electrode surface and cause clogging. , (Ba・Sr・
Ca)O is covered, and the electron emissivity of the electrode becomes extremely poor, making it extremely difficult for discharge to occur. However, as described above, if a protective gas layer is provided around the electrodes, the reaction products are prevented from covering the electrodes, so that the discharge can be maintained well.

In the above embodiment, the discharge gas serves as the electrode protection gas, but of course gases with different component compositions may be flowed from separate supply ports, and the discharge gas serves as the electrode protection gas. It is also possible to place an electrode for plasma diet, which also serves as a plasma generator, toward the discharge space, and use the emitted light from the plasma of the plasma diet as stimulation light.

Various deposited films and substrates may be selected depending on the purpose and use. For example, if a silicon wafer is used as the substrate and a molecular species containing nitrogen such as ammonia and silicon tetrahydride are included as a photochemically reactive gas, a silicon nitride protective film can be formed on the silicon wafer. Additionally, the apparatus of the present invention can be used to form metal films, insulating films, protective films, and amorphous material layers on substrates made of various materials. In addition, if there is a possibility that various molecular species and ionic species generated by the discharge will pass through the communication space 6 toward the substrate and deteriorate the performance of the deposited film, the communication space 6 should be closed to the above molecular species and ionic species. Just design it a little longer so that it maintains a distance longer than the mean free path of .

As can be understood from the description of the above-mentioned embodiments, the present invention provides a discharge space for producing stimulating light that causes a photochemical reaction, and a passage space for a photochemically reactive gas that receives the stimulating light and participates in the photochemical reaction. Surrounded by a single container via the joint space, the stimulating light directly irradiates the substrate and the photochemically reactive gas near the substrate without transmitting anything, and the photochemical reaction products are deposited as a vapor deposited film on the inner wall of the container and the substrate. Even if you do,
There is no formation of deposits that would interfere with irradiation with the stimulating light. Moreover, since the reaction product is designed to prevent the electrodes from being covered, a long-life "discharge built-in" chemical vapor deposition device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the embodiment device viewed from the direction in which the substrate 1 moves, and FIG. 2 is a schematic explanatory diagram of the same device viewed from the direction perpendicular to the direction in which the substrate 1 moves. FIG. 3 is an explanatory diagram of an example of a method for attaching the electrode 2 to the container 3. In the figure, 1 is a substrate, 2 is an electrode, 3 is a container, and 9
indicate the respective heaters.

Claims (1)

[Scope of Claims] 1. A discharge space that generates stimulating light that causes a photochemical reaction and a passage space for a photochemically reactive gas that receives the stimulating light and participates in the photochemical reaction are surrounded by the same container, and directed toward the discharge space, A chemical vapor deposition apparatus comprising a discharge electrode and a protective gas supply mechanism for supplying the electrode protective gas around the electrode.