JPS61186476A - Photochemical reaction device - Google Patents

Abstract

PURPOSE:To prevent the deposition of the reactant on a plate-shaped body by segmenting the inside of a vessel to a light source chamber and substrate chamber and ejecting a photoreactive inert gas introduced into the light source chamber through the holes of the gas permeable and UV transmittable plate- shaped body into the substrate chamber. CONSTITUTION:The inside of the chamber 1 is segmented to the substrate chamber 1a and the light source 1b by the gas permeable and UV transmittable perforated plate 5. The photoreactive inert gas such as Ar is introduced into the chamber 1b where the gas is used as a discharge gas. The photoreactive gas such as silane gas is introduced into the substrate chamber 1a. The stable photochemical vapor growth is made possible without deposition of amorphous silicon on the plate 5 and without hindering the transmission of UV rays even after the long-term operation according to the above-mentioned method.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a photochemical reaction device.

(b) Background of the Invention Recently, research has been conducted into methods for forming vapor-deposited films of amorphous silicon 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 insulating films and protective films such as silicon oxide and silicon nitride, and various vapor deposition methods have been proposed depending on the application. The growth method (photo-CVD method) has advantages such as a fast film formation speed and the ability to form a uniform film even on large areas, and in particular has better physical properties than films formed by conventional plasma CVD. It has been known that this method can be deposited at lower temperatures, and has recently attracted particular attention.

(/→ Prior Art) In a conventional vapor phase growth or deposition method using a photochemical reaction, a substrate is placed in a reaction vessel that has a window that allows ultraviolet rays to pass through, a photoreaction gas is caused to flow, and the process is carried out from outside the vessel.
This method photochemically reacts the nuclear gas with an ultraviolet light source and causes the reaction product to grow on the substrate in a vapor phase.The film formation rate is extremely fast and a uniform film can be formed even on large areas.
However, on the other hand, it was found that the reaction product also accumulates on the transmission window of the container, which significantly inhibits the transmission of ultraviolet rays.

For this reason, in the past, deposits on the transparent window were suppressed by coating the transparent window with a special oil or by flowing an inert gas such as argon.

B) Problems to be Solved by the Invention The method of applying oil described above makes it easy to remove deposits, but the effect of preventing the deposit itself is small, and the method of applying inert gas to 70% However, it is difficult to arrange the inert gas nozzle so that the ultraviolet rays are not blocked and spray them uniformly onto the transparent window, and these measures are insufficient. An object of the present invention is to provide a photochemical reaction device that has a simple structure and does not inhibit the transmission of ultraviolet light due to the accumulation of reaction products on the ultraviolet light transmission window. The light source chamber is partitioned by a gas-permeable and ultraviolet-transparent plate-like body, one of which is a light source chamber in which an ultraviolet light source is installed, and the other a substrate chamber in which a substrate to be deposited is placed. First, a photoreactive gas is introduced into each substrate chamber from the outside, and these gases are discharged from the substrate chamber to create a gas flow of inert gas from the light source chamber to the substrate chamber, and the inert gas flows into the plate shape. The jet flow from the body prevents reaction products from depositing on the surface of the plate-like body, and photochemical vapor phase growth can be carried out stably for a long time without reducing the transmission of ultraviolet rays. .

(f) Function: The container consists of two halves internally divided by a gas-permeable and ultraviolet-transparent plate-like body, and the photoreactive inert gas is introduced into the light source chamber, and the gas-permeable and ultraviolet-ray permeable gas is The gas flows from the gas passage holes of the permeable plate to the substrate chamber in which the substrate to be deposited is placed. On the other hand, the photoreactive gas is introduced from the outside into the substrate chamber where the substrate to be film-formed is placed, and the overall gas flow is from the light source chamber to the substrate chamber. And by the jet flow of inert gas from the gas passage hole of the ultraviolet-transparent plate-like body,
Reactive substances, reaction intermediates, and final reactants can be kept away from this plate, so they can be prevented from accumulating on the light source chamber and the partition plate, and UV light can be stably applied to the substrate to be coated for a long period of time. It exerts an effect that can reach the surface.

(g) Examples Hereinafter, the present invention will be specifically explained based on examples shown in the drawings.

The container 1 consists of a substrate chamber 1a in which a substrate to be film-formed is installed, and a light source chamber 1b that generates ultraviolet rays. ), and a substrate support stand 9 made of quartz glass is arranged in the center of the interior so as to be movable up and down. A porous plate 5 made of a crystal plate such as CaF, LiF, MgF, etc. that is highly transparent to ultraviolet rays is provided below, and partitions the gas permeable and ultraviolet ray transparent plate h1b and the substrate chamber 1a. are doing. Discharge electrodes 3, 3 are installed in the light source chamber 1b, and argon, a photoreactive inert gas, is introduced through the introduction hole 2 in which the discharge electrode 6.3 is installed, and is used as a discharge gas. In particular, in order to strengthen the short-wavelength ultraviolet rays, about 1, for example, about 1 H of hydrogen may be mixed. The porous plate 5 is provided with a large number of ejection holes 51, from which the photoreactive inert gas for discharge is ejected into the upper substrate chamber 1a. This ejection hole 51 may be in the form of a slit, etc., as long as it is made of a material that transmits ultraviolet rays and allows gas to be ejected uniformly from its surface. The ultraviolet light generation source in the light source chamber 1b may be an electrodeless discharge or a light source such as an ordinary low-pressure mercury lamp, and in short, any ultraviolet light source that emits the wavelength necessary for photochemical reaction may be used.

A temperature regulator (not shown) is attached to the substrate support stand 9, and the substrate 7 supported by this is an alumina plate having an outer diameter of 1605 W and is heated to approximately 150°C. Note that this substrate support stand 9 can be made rotatable like a turntable or movable within the container 1, and the substrates 7 can be taken in and out using a transport mechanism, so that a large number of substrates 7 can be processed efficiently. . The introduction hole 6 is used alone or together with a carrier gas for a substrate 7 held in a shell/gather for a decomposition vapor layer.
It is placed opposite to the area where is placed. It is preferable to provide a temperature regulator in this introduction hole 6.6 to optimally adjust the temperature of the scum, since this will enhance the photochemical reaction.

In the above apparatus, the pressure inside the container 1 is reduced and argon, which is a photoreactive inert gas, is introduced from the introduction hole 2 at 200 SC.
Introduced from CM to 2000SCCM, discharge electrode 6
, 6, a discharge region 4 is formed and n1 ultraviolet rays are generated. And introduction hole 6.6 area, 5SCCM to 100
SCCM 7 run gas is introduced, and the substrate 7 is irradiated with ultraviolet rays that have passed through the porous plate 5, and the Elysira/gas is photodecomposed and amorphous silicon is deposited on the substrate 7. For example, if the power consumption due to discharge is 1 km, the discharge area is 4.
When formed, the substrate 7, which is about 53m long, has a thickness of 160n.
Ultraviolet rays with a wavelength of less than m are irradiated with an intensity of 10 ''/d, and a film is formed at an extremely fast rate of 1 nr s or more. At this time, a portion of the photoreactive gas descends and travels toward the perforated plate 5, but as shown by the arrow in FIG. Since argon gas is ejected from the ejection hole 51, the photoreactive gas passes through the ejection hole 51 and enters the light source chamber 1bVc.
Ili! Not only is the inert gas not injected into the reduced pressure space of the substrate chamber 1'a from the ejection hole 51, the inert gas expands to the left and right at the same time as the ejection, and flows to the upper surface of the perforated plate 5. No reaction products are deposited. In this way, since amorphous silicon does not accumulate on the porous plate 5, it does not fog up even during long-time operation, and the transmission of ultraviolet rays is not inhibited.

Note that the crystal plate used as the porous plate 5, such as CaF, has low heat resistance, so when generating ultraviolet rays by the discharge shown in this example, the placement position must be designed so that it will not be damaged by the heat of the discharge arc. However, when using a low-pressure mercury lamp using, for example, sapphire for the arc tube, the heat generated from the lamp is relatively small, so it can be used without special consideration. In addition, when a rung using sapphire or synthetic quartz for the arc tube is used as the ultraviolet light source in place of the ultraviolet light emitting discharge section 4, porous #L5tfi 7 aier or synthetic quartz may be used.

(E) Detailed Description of the Invention As described above, the present invention provides a substrate chamber having a supply and discharge mechanism for photochemically reactive gas in a container, and a light source chamber that generates ultraviolet rays by discharging a photoreactive inert gas. A light-reactive inert gas is introduced into the light source chamber, a photo-reactive gas is introduced into the substrate chamber from the outside, and the gas flow from the light source chamber to the substrate chamber is controlled as a whole. Since the transverse wave is made so that inert gas is ejected from the plate-shaped body, the inert gas uniformly flows over the surface of the perforated plate without blocking ultraviolet rays by nozzles, etc., so that photoreactions are generated. Not only does the material not enter the light source chamber, but it also does not accumulate on the plate. Furthermore, since the pressure difference between the light source chamber and the substrate chamber can be made small, there is no need to withstand a pressure difference of nearly 1 atm as in a normal photo-CVD window, and the strength of the plate-shaped body can be made relatively small. The economic effects are also significant.

Therefore, according to the present invention, it is possible to provide a photochemical reaction device that has a simple structure, does not inhibit ultraviolet transmission, and can be operated stably over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a perspective view of a perforated plate, and FIG. 6 is an explanatory diagram of an inert gas jetting situation. 1...-Container 1a... Substrate chamber 1b... Light source chamber 2
... Inert gas introduction hole 3 ... Discharge electrode 4 ... Ultraviolet light emitting discharge section 5 ... Porous plate 6 ... Photoreactive gas introduction hole 7 ... Film-forming substrate 8 ... Exhaust hole 9...
Substrate support stand 51... gas ejection hole

Claims (1)

[Claims] The inside of the container is partitioned by gas-permeable and ultraviolet-transparent plate-like bodies, one of which is a light source chamber where an ultraviolet light source is installed, and the other is a substrate chamber where a substrate to be deposited is placed, and a photoreactive inert gas is used. A photoreactive gas is introduced into the light source chamber and a photoreactive gas is introduced into the substrate chamber from the outside, and these gases are discharged from the substrate chamber to create a gas flow of inert gas from the light source chamber to the substrate chamber. A photochemical reaction device characterized in that the jet flow from the plate-like body prevents reaction products from being deposited on the surface of the plate-like body.