JPS60209246A - Photochemical reaction device - Google Patents

Abstract

PURPOSE:To prevent the deposition of the formed material on an ultraviolet transmissive window when the photochemical reaction is carried out by utilizing the mercury-sensitized reaction and to eliminate the hindrance to the transmission of ultraviolet rays by providing a mesh member which can be cooled in the vicinity of the transmissive window in a reaction vessel. CONSTITUTION:A substrate 4 is arranged in a reaction vessel 1 having an ultraviolet transmissive window 14, and a photoreactive gas (e.g., SiH4) is introduced from an introducing hole 11. Said gas is allowed to react photochemically with an ultraviolet ray source 3 at the outside of the reaction vessel 1, and the reaction product is deposited or vapor-deposited on the substrate 4. In said photochemical reaction device, a mesh member 5 which can be cooled is provided in the vicinity of the transmissive window 14 in the reaction vessel 1. The formed material is not deposited on the ultraviolet transmissive window when the photochemical reaction is carried out by utilizing the mercury-sensitized reaction, and the transmission of ultraviolet rays is never hindered.

Description

[Detailed description of the invention] The present invention relates to a photochemical reaction device.

Recently, research has been carried out on methods of forming vapor deposited amorphous silicon films used in photosensitive drums of electronic copying machines, solar cells, and the like. On the other hand, vapor deposition methods are also used to form various insulating films and pupil retention films, and various vapor deposition methods have been proposed depending on the application. This method has the advantage of being extremely fast in forming a film and being able to form a uniform film even over a large area, and has recently attracted particular attention.

In conventional chemical vapor deposition or deposition methods that utilize photochemical reactions, a substrate is placed inside a container with a window that transmits ultraviolet rays, a gas for photoreaction is passed through the container, and the gas is subjected to a photochemical reaction using an ultraviolet light source from outside the container. The reaction product is vapor-deposited or deposited on the substrate. When using 5iHn, which is inexpensive and easily available, as a photoreactive gas for producing amorphous silicon,
Because the reaction does not proceed sufficiently even when irradiated with ultraviolet light with a wavelength of 254 nm or 185 nm, mercury is added to rapidly decompose 5iHn through a mercury sensitization reaction. This method has the major advantages as mentioned above. However, on the other hand, it has been found that the reaction product also accumulates on the ultraviolet light transmission window, which significantly inhibits the transmission of ultraviolet light. For this reason, in the past, vapor deposition or deposition on the transmission window was suppressed by flowing an inert gas such as argon or applying oil to the transmission window, but these measures were not effective enough. I couldn't do it.

Therefore, the present invention has a simple structure, and when a photochemical reaction is carried out using a mercury sensitization reaction, no products are deposited on the ultraviolet transmitting window, and the photochemical reaction does not inhibit the transmission of ultraviolet light. The objective is to provide an apparatus, and 'this purpose is to place $, @ in a reaction vessel with an ultraviolet ray transmission window, to flow the original reactive gas containing mercury, and to use an ultraviolet light source outside the reaction vessel to irradiate the gas. This is achieved by a photochemical reaction device in which a coolable mesh member is disposed near a transmission window in a reaction vessel, and the reaction product is vapor-deposited or deposited on a substrate. The present invention was developed by focusing on the fact that when mercury vapor reaches a low-temperature mesh member, its vapor pressure drops rapidly, so it is trapped there and does not reach the transmission window. The purpose can be easily achieved, for example, by using a hollow wire to form a mesh and passing a cooling medium through the mesh. The ultraviolet rays pass through the spaces in the mesh member and are irradiated onto the substrate, but if the mesh is made denser or denser, the amount of ultraviolet light passing through can be adjusted arbitrarily, so the amount of irradiation on the substrate can be made uniform, On the other hand, it is also possible to make partial changes.

The present invention will be specifically described below based on embodiments shown in the drawings.

The reaction vessel 1 is provided with an introduction hole 11 for the original reactive gas and an exhaust hole 12 connected to a pressure reducing device, and a substrate support stand 13 made of quartz glass is arranged in the center of the interior so as to be movable up and down. . The upper surface is provided with an ultraviolet light transmitting window 14 made of quartz glass, and a lamp body 2 is integrally connected to the upper part of the window 14, and an ultraviolet lamp, which is an ultraviolet light source, is connected to the ceiling through a reflective member 21. 5 are arranged in parallel. Here, the UV lamp 5 has a tube diameter of 18-1 and a lighting start voltage! 1
This is a low-pressure mercury lamp with an AC lighting of 50V, a lighting voltage of 90V, and a current of 5N, but it is not limited to this, and may also be an electrodeless lamp device or a plasma generator, in short, it generates a predetermined amount of ultraviolet rays. 6 Also, if necessary, a temperature regulator (not shown) may be installed on the board support stand 13 in the lamp body 2. The substrate 4 supported by this is an alumina plate having an outer diameter of 160M and is heated to about 150°C. In addition, this substrate support stand 15 may be made rotatable like a turntable or movable within the reaction vessel 1,
A large number of substrates 4 can be efficiently processed by loading and unloading the substrates 4 with the transport mechanism. A mixture of argon as a carrier gas, mercury gas as a photosensitizer, and silicon tetrahydride as a decomposition vaporization gas is supplied from the introduction hole 11 into the reaction vessel 1. When using reactive gases, it is preferable to provide a plurality of introduction holes 11 to introduce each gas individually and mix them within the reaction vessel 1. It is preferable that a temperature regulator is provided in the introduction hole 11 to adjust the temperature of each dreg to an optimum temperature to promote the photochemical reaction.

Next, a mesh member 5 is placed near the transmission window 14 in the reaction vessel 1 f! 4. General 6.0.1A.2 This mesh member 5 is made by knitting thin metal pipes 51 into a mesh shape, which is stretched inside a hollow frame 52. The aperture ratio of this mesh is about 90%, so it is not a problem that the transmission of ultraviolet rays is obstructed by this, but if the mesh is made coarser and denser, it is possible to partially change the transmittance of ultraviolet rays. Therefore, the amount of irradiation on the substrate 4 can be determined arbitrarily. The hollow frame 52 has an inlet pipe 53 and an outlet pipe 5.
4 is connected, and a gas or liquid cooling medium is introduced from the outside to cool the mesh member 5. However, the mesh member 5 is not limited to this structure; for example, it may be simply a wire mesh stretched over it and cooled by blowing cooling gas onto it; in short, it may be a mesh-like member that can be cooled. .

The pressure inside the reaction vessel 1 is then reduced to several mHg or less, and the ultraviolet lamp 3 is turned on. Most reaction vessel 1
The photochemical reaction may be caused under normal pressure without reducing the pressure inside.

Then, from the introduction hole 11, argon with a partial pressure of 5 wm Hg, silicon tetrahydride with a partial pressure of 5 wm HH, S X 10-'
Mercury vapor of wx Hg is introduced, and silicon tetrahydride is photodecomposed by irradiation with ultraviolet rays, and amorphous silicon is vapor-deposited or deposited on the substrate 4. At this time, a portion of each gas rises and moves toward the transmission window 14, but on the way, it attempts to pass through the mesh member 5. However, since the mesh member 5 is cooled, the mercury vapor is also cooled and its vapor pressure decreases. For example, the vapor pressure of mercury at 0°C is 2 x 10-' wm Hg, and the mesh member 5
If it is cooled to 0℃, the vapor pressure of mercury in this part is 1
/1° or less, and the amount of mercury vapor that can pass through the mesh member 5 is extremely small. Therefore, since no photosensitizing effect is performed on the surface of the transmission window 14, silicon tetrahydride is not decomposed even if it is irradiated with ultraviolet light having a wavelength of 185 nm or 254 nm from the ultraviolet lamp 5. For this reason, the transmission window 1
4. Since amorphous silicon does not accumulate, it does not fog up even after long-term operation, and the transmission of ultraviolet rays is not inhibited.

As explained above, in the present invention, since the coolable mesh member is disposed near the transmission window in the reaction vessel, mercury vapor is captured by the mesh member and does not reach the transmission window, and the surface of the transmission window is In this case, the photochemical reaction hardly progresses, so no products are deposited. Therefore, according to the present invention, the structure is simple, and when a photochemical reaction is performed using a mercury sensitization reaction, no product is deposited on the ultraviolet transmitting window.
A photochemical reaction device in which transmission of ultraviolet rays is not inhibited can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a perspective view of a mesh member. 1... Reaction container 2... Light body 6... Ultraviolet lamp 4... Substrate 5... Mesh member 13... Substrate support stand 14... Transmission window Fig. 1 32
1 Figure 2 Procedural amendment (voluntary) August 10, 1980 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case 1981 Patent Application No. 63411 2, Title of the invention Photochemical reaction device 3, Person making the amendment Relationship to the case Patent applicant 6. Number of inventions increased by amendment N/A 7. In the detailed description of the invention in the specification subject to amendment, page 5, line 18, ``Structure that allows gas to flow in space "can be set up" to "flow gas into the space,
A mechanism that can reduce the pressure in the space may be provided. ”. that's all

Claims (1)

[Claims] 1. Placing a substrate in a reaction vessel having an ultraviolet ray transmission window, flowing a photoreactive gas containing mercury, causing the gas to undergo a photochemical reaction using an ultraviolet light source outside the reaction vessel, and producing the reaction product. A photochemical reaction device for depositing or vapor-depositing a substance on a substrate, the photochemical reaction device comprising a coolable mesh member disposed near a transmission window in a reaction vessel. 2. The photochemical reaction device according to claim 1, wherein the mesh member is a hollow wire rod shaped into a mesh, through which a cooling medium passes. 5. The photochemical reaction device according to claim 1, wherein the mesh member has a density in its mesh, so as to control the distribution of the ultraviolet cotton on the substrate.