JP2008262967A - Vapor phase growth method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase deposition method by which thermal environment in a reaction chamber is kept uniform, mixing of particles is prevented and stable film formation can be established, and to provide a rotation-revolution system vapor phase deposition apparatus that has such a structure capable of adopting this method. <P>SOLUTION: The vapor phase deposition method is used to rotate a susceptor, introduce a material gas from a gas inlet pipe while a substrate is being heated, grow a thin film on the surface of the substrate and repeat the film formation every time the substrate is changed anew. When the operation of film formation is completed, a partitioning plate and a susceptor cover are removed from a chamber, clean ones are arranged inside the chamber before the next operation is started. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vapor phase growth method and apparatus, and more particularly to a vapor phase growth method and apparatus for heating a substrate installed in a reaction chamber to a predetermined temperature and supplying a predetermined source gas to grow a thin film on the substrate surface. .

As a vapor phase growth apparatus, a susceptor is rotatably disposed in a lower portion of a chamber formed in a flat cylindrical shape, and a substrate holder for holding a substrate is disposed on the outer periphery of the susceptor so as to be capable of rotating and revolving. A so-called self-revolving vapor phase growth apparatus is known in which a gas introduction part for introducing a source gas from the central part of the susceptor toward the outer peripheral part is disposed at the upper part. The vapor phase growth apparatus introduces a predetermined source gas into the chamber from the gas introduction part while rotating and rotating the susceptor heated to a predetermined temperature and rotating the substrate held by the substrate holder. A thin film is grown on the surface (see, for example, Patent Document 1). Also, in such a vapor phase growth apparatus, a glove box is continuously provided in the film forming chamber in order to easily remove deposits attached to members such as a susceptor and a flow channel in the film forming chamber for forming a film on the substrate surface. What has been proposed.
JP 2006-108312 A JP-A-2005-236093

  In a reaction chamber of a general vapor phase growth apparatus, a surface facing a high-temperature substrate is formed of quartz glass having excellent heat resistance and low reactivity with a source gas. Since this quartz glass has almost no infrared absorption, the decomposition product of the raw material adheres to the surface in contact with the raw material gas after repeated vapor phase growth several times from the new state or the state after cleaning, and the reaction chamber Until the substrate facing surface becomes dirty to some extent, heat (infrared rays) escapes to the outside of the reaction chamber, so that the thermal environment is not stable and the reproducibility of the thin film is not sufficient.

  For this reason, when using a reaction chamber that is new or cleaned, the surface in contact with the source gas in the reaction chamber is intentionally soiled by introducing the source gas into the reaction chamber, and is in a thermally stable state. And that is done. For this reason, not only productivity is lowered, but also material costs are greatly affected. On the other hand, when the surface in contact with the source gas in the reaction chamber, particularly the substrate facing surface, is contaminated with decomposition products and the like, the thermal environment in the reaction chamber becomes stable as described above, but is caused by the deposits. Particles are mixed in the thin film and cause the performance of the thin film to deteriorate.

  Further, when a member constituting the reaction chamber is taken out from the film formation chamber using a glove box as in the vapor phase growth apparatus described in Patent Document 2, a general small horizontal type vapor phase growth apparatus is compared. However, in the above-mentioned self-revolution type vapor phase growth apparatus, the members constituting the reaction chamber are large, and the reaction chamber is entirely formed of quartz glass as in the past, or the entire chamber is formed of carbon. It was difficult to take out the susceptor into the glove box.

  Accordingly, the present invention provides a vapor phase growth method capable of performing stable film formation by keeping the thermal environment in a reaction chamber constant and preventing mixing of particles, and a self-revolution having a structure capable of implementing this method. An object of the present invention is to provide a vapor deposition apparatus of the type.

  In order to achieve the above object, a vapor phase growth method of the present invention is a vapor phase growth method in which a susceptor holding a substrate is accommodated in a reaction chamber, and a raw material gas is introduced into the reaction chamber to grow a thin film on the substrate surface. When performing the film forming operation for growing the thin film, each film forming operation is started after the member in contact with the source gas in the reaction chamber is a clean member.

  Further, the vapor phase growth apparatus of the present invention includes a disc-shaped susceptor that rotates while holding a plurality of substrates on the outer peripheral portion, and a raw material gas that is disposed to face the surface of the susceptor so as to face the outer peripheral portion from the susceptor center. In a vapor phase growth apparatus in which a gas introduction pipe to be introduced is accommodated in a flat cylindrical chamber, the chamber is disposed on the susceptor side and opened on the side opposite to the susceptor, and the chamber body is hermetically sealed. The chamber lid is divided into a chamber lid, and an insertion port through which the gas introduction tube is inserted is provided at the center of the chamber lid, and a cylinder is formed between the opening edge of the insertion port and the upper portion of the gas introduction tube. The chamber lid is formed so as to be movable up and down by airtightly attaching a cylindrical expansion and contraction member, and a partition plate that is divided into a plurality of parts is provided between the tip of the gas introduction pipe and the outer peripheral wall of the chamber body The chamber is divided into upper and lower parts, a reaction chamber is formed on the susceptor side, a susceptor cover divided into a plurality of parts is provided on the reaction chamber side surface of the susceptor, and the glove box is connected to the chamber through a partition door. The partition plate and the susceptor cover formed in the chamber from the inside of the glove box to the inside of the glove box from the inside of the glove box with the chamber lid being separated from the chamber body. It is characterized in that it is formed so that it can be taken out from the glove box and mounted in the chamber.

  According to the vapor phase growth method of the present invention, the member in contact with the source gas is replaced with a clean member every time the film forming operation is performed, so that the thermal environment in the reaction chamber during the film forming operation is kept constant. And a stable quality thin film can be produced. Further, by using a clean member from which deposits have been removed, there is no possibility that particles resulting from deposits will be mixed into the thin film, and the performance of the thin film will not be degraded. Further, in the vapor phase growth apparatus of the present invention, the partition plate and the susceptor cover that come into contact with the source gas during the film forming operation are divided and formed so as to be movable between the film forming chamber and the glove box. After the film forming operation is completed, the partition plate and the susceptor cover are removed from the chamber, and then the new partition plate and the clean partition plate and the susceptor cover after cleaning can be disposed at predetermined positions in the chamber.

  FIG. 1 is an explanatory view showing an example of a vapor phase growth apparatus according to the present invention. In this vapor phase growth apparatus, a susceptor 13 made of disc-shaped carbon and a concentric circle on the outer peripheral portion of the susceptor 13 are equidistantly disposed in a flat cylindrical chamber 12 having a gas introduction pipe 11 disposed in the upper center. A plurality of substrate holders 14 are disposed, and a partition plate 16 is provided so as to face the susceptor 13 and divide the chamber 12 vertically and form a reaction chamber 15 on the susceptor 13 side.

  The chamber 12 is formed of stainless steel or the like having excellent corrosion resistance, and is airtightly attached to the upper portion of the peripheral wall of the chamber body 17 through an O-ring. The chamber lid 18 is divided and formed. A rotation drive shaft 19 for rotating the susceptor 13 is provided at the center of the bottom of the chamber body 17, and the substrate holder 14 holding the substrate 20 is moved by rotating the susceptor 13 with the rotation drive shaft 19. It revolves around the center of 13 and rotates by a rotating gear mechanism provided on the outer circumference of the susceptor 13.

  A heater 21 for heating the substrate 20 is disposed in a ring shape below the substrate holder 14, and a ring-shaped exhaust passage 22 is provided on the outer peripheral side of the susceptor 13. A cylindrical guide tube 23 for inserting the gas introduction pipe 11 is airtightly provided at the center of the chamber lid 18.

  The partition plate 16 is divided into a plurality of parts in the circumferential direction and the radial direction, and has a large-diameter ring-shaped outer peripheral side partition plate 16a arranged on the outer peripheral side, and a plurality of parts divided in the circumferential direction on the inner peripheral side thereof. And a small-diameter ring-shaped inner peripheral side partition plate 16b in combination of the fan-shaped divided bodies. The outer peripheral side partition plate 16 a is fixed at a predetermined position in a state where the outer peripheral edge is placed on the inner periphery of the peripheral wall of the chamber body 17. The inner peripheral side partition plate 16 b is disposed at a position facing the substrate 20, and the outer peripheral edge thereof is placed on the inner peripheral edge of the outer peripheral side partition plate 16 a, and the inner peripheral edge of the gas introduction pipe 11. It is mounted on the outer peripheral edge of the nozzle 24 provided at the lower end and is detachable, and a knob portion 16c projects from the upper surface.

  A susceptor cover 25 that is divided into a plurality of parts in the circumferential direction and the radial direction is placed on the upper surfaces of the susceptor 13 and the substrate holder 14. The susceptor cover 25 is formed of a holder cover 25a that covers the upper surface of each substrate holder 14 and rotates together with the substrate holder 14, and a cover body 25b that covers the upper surface of the susceptor 13 other than the portion covered by the holder cover 25a. The holder cover 25a is provided with an opening for holding the substrate 20.

  The chamber lid 18 is attached to the elevating means 26 via a plurality of brackets 26 a provided on the outer peripheral portion, and is cylindrical between the guide cylinder 23 and the upper flange 11 a provided on the upper part of the gas introduction pipe 11. The bellows 27 is attached in an airtight manner, and the opening of the chamber main body 17 can be opened by moving the elevating means 26 in the ascending direction and raising the chamber lid 18 while the bellows 27 is contracted.

  The gas introduction pipe 11 is composed of a multiple pipe in which a plurality of pipes having different diameters are concentrically arranged to define a plurality of gas flow paths, and the upper outer periphery of the multiple pipe is airtightly held by the upper flange 11a. Has been. The nozzle 24 is provided at the lower end of the gas introduction pipe 11 so as to expand in the outer circumferential direction and introduce the source gas in parallel with the upper surface of the susceptor from the center of the susceptor 13 toward the outer circumference. A step portion for mounting the inner peripheral side partition plate 16b is provided on the outermost peripheral edge of 24.

  In the self-revolution type vapor phase growth apparatus formed in this way, the entire chamber 12 is accommodated in the film forming chamber 30, and a glove box 32 is connected to the film forming chamber 30 through a partition door 31. The inner partition plate 16b and the holder cover 25a can be attached and detached by a glove operation from the inside of the glove box 32 with the chamber lid 18 raised. In the film forming chamber 30 and the glove box 32, a purge gas for purging atmospheric components to the inside flows.

  When a thin film was grown on the substrate 20 using this vapor phase growth apparatus, when one film forming operation was completed, the chamber lid 18 was raised and the partition door 31 was opened to form a thin film. While taking out the substrate 20, the inner peripheral side partition plate 16b and the holder cover 25a are taken out from the film forming chamber 30 to the glove box 32, and a new or clean inner peripheral side partition plate prepared in advance in the glove box 32 is prepared. 16b and the holder cover 25a are arranged at predetermined positions in the chamber 12, and the next film forming operation is started in a state where a new substrate 20 is set at the predetermined position.

  As described above, by using the inner partition plate 16b and the holder cover 25a in a clean state for each film forming operation, the thermal environment in the reaction chamber 15 during the film forming operation can be kept constant. In addition, since the film forming operation is performed in a state where no deposits are attached, particles caused by the deposits are not mixed into the thin film. Therefore, a high-quality thin film with good reproducibility can be stably obtained, and the yield can be improved. Moreover, since it can suppress that the inner peripheral side partition plate 16b and the holder cover 25a are eroded by a deposit | attachment, the lifetime of these components can also be extended.

  The size and shape of the glove box 32 and the partition door 31 and the attachment position to the film forming chamber 30 may be set according to conditions such as the size of the vapor phase growth apparatus, and a plurality of glove boxes 32 are connected in series. You can also Moreover, the division | segmentation number and division | segmentation shape of the partition plate 16 and the susceptor cover 25 are arbitrary, What is necessary is just to make it the magnitude | size which can be handled with a glove, avoiding the gas introduction pipe | tube 11 and the raising / lowering means 26. Further, the glove box 32 may be detachably provided with a transfer container for transferring the partition plate 16 and the susceptor cover 25 taken out from the chamber 12 to the cleaning place.

The partition plate 16 and the susceptor cover 25 removed from the chamber 12 can be cleaned by any method, but a gas containing at least one or more chlorine-based gases such as Cl ₂ , HCl, SiCl ₄ , and SiCl ₂ H _2. It is preferable to use a method of removing deposits by thermal decomposition reaction. The chlorine-based gas can be used after being diluted with a gas that does not react with these chlorine-based gases, for example, an inert gas such as nitrogen or argon.

An undoped GaN film was grown on a sapphire substrate under atmospheric pressure using the vapor phase growth apparatus having the structure shown in FIG. The film structure was GaN (4 μm) / low temperature growth GaN buffer layer (25 nm) / 2 inch C-plane sapphire substrate. The partition plate and susceptor cover in a clean state were set, and the film forming operation was repeated four times. Cleaning of the partition plate and susceptor cover is performed at 800 ° C. using a dedicated pyrolysis furnace different from the vapor phase growth apparatus, with an etching gas of 5% chlorine and 95% nitrogen distributed at 6 liters per minute. It went for 1 hour. Table 1 shows the SIMS analysis results in the GaN film, and Table 2 shows the measurement results of the number of particles in the GaN film.

  An LED film having an InGaN / GaN multiple quantum well structure with 6 periods was continuously formed four times on the substrate under atmospheric pressure. The structure of the LED film is Mg—GaN (thickness 100 nm) / 6 × [InGaN (thickness 2.2 nm) / GaN (thickness 10 nm)] / Si-doped GaN (thickness 4 μm) / low-temperature grown GaN (thickness) 25 nm) / 2 inch C-plane sapphire substrate. High purity ammonia was used as the nitrogen source gas, hydrogen and nitrogen mixed gas was used as the carrier gas, trimethylindium was used as the In source material, trimethylgallium was used as the Ga source material, and nitrogen-based 10 ppm silane was used as the Si source material.

FIG. 2 shows the relationship between the PL emission wavelengths obtained by the photoluminescence measuring device when the film was washed four times continuously using the one washed only for the first time and when the film washed every time was used. Table 3 shows the current injection light emission output in the LED film obtained by each film forming operation. Furthermore, the number of particles in each LED film obtained by the fourth film formation was about ¼ when washed each time as compared to the case without washing.

  A six-period InGaN / GaN multiple quantum well structure film was continuously formed four times on the substrate under atmospheric pressure. The structure of the film is / 6 × [InGaN (thickness 2.5 nm) / GaN (thickness 12 nm)] / Si-doped GaN (thickness 4 μm) / low-temperature grown GaN (thickness 25 nm) / 2 inch C-plane sapphire substrate It was. High purity ammonia was used as the nitrogen source gas, nitrogen as the carrier gas, trimethylindium as the In source material, trimethylgallium as the Ga source material, and nitrogen-based 10 ppm silane as the Si source material.

FIG. 3 shows the relationship between the PL emission wavelengths obtained by the photoluminescence measuring apparatus when the film was washed four times continuously using the one washed only for the first time and when the film washed every time was used. If the cleaning is not performed each time, the wavelength gradually shifts to the short wave side, so that temperature correction and trimethylindium supply amount correction are required for each film forming operation. Table 4 shows the measurement results of the number of particles in the film.

It is explanatory drawing which shows one example of the vapor phase growth apparatus of this invention. It is a figure which shows the relationship of each PL light emission wavelength calculated | required with the photoluminescence measuring apparatus when forming into a film 4 times continuously using what was wash | cleaned only the first time, and when using what was wash | cleaned every time. It is a figure which shows the relationship of each PL light emission wavelength calculated | required with the photoluminescence measuring apparatus when forming into a film 4 times continuously using what was wash | cleaned only the first time, and when using what was wash | cleaned every time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gas introduction pipe, 11a ... Upper flange, 12 ... Chamber, 13 ... Susceptor, 14 ... Substrate holder, 15 ... Reaction chamber, 16 ... Partition plate, 16a ... Outer peripheral side partition plate, 16b ... Inner peripheral side partition plate, 16c DESCRIPTION OF SYMBOLS ... Picking part, 17 ... Chamber main body, 18 ... Chamber lid, 19 ... Rotary drive shaft, 20 ... Substrate, 21 ... Heater, 22 ... Exhaust passage, 23 ... Guide cylinder, 24 ... Nozzle, 25 ... Susceptor cover, 25a ... Holder Cover, 25b ... Cover body, 26 ... Elevating means, 26a ... Bracket, 27 ... Bellows, 30 ... Deposition chamber, 31 ... Partition door, 32 ... Glove box

Claims (2)

  In a vapor phase growth method in which a susceptor holding a substrate is accommodated in a reaction chamber, and a raw material gas is introduced into the reaction chamber to grow a thin film on the substrate surface, when performing a film forming operation for growing the thin film, A vapor phase growth method characterized in that each film forming operation is started after a member in contact with the source gas in a reaction chamber is made a clean member.   A disc-shaped susceptor that rotates while holding a plurality of substrates on the outer periphery, and a gas introduction pipe that is disposed opposite to the surface of the susceptor and introduces a source gas from the center of the susceptor toward the outer periphery. In the vapor phase growth apparatus accommodated in the chamber, the chamber is divided into a chamber body disposed on the susceptor side and having an opening on the anti-susceptor side, and a chamber lid that is airtightly attached to the opening of the chamber body. The chamber lid is provided with an insertion port through which the gas introduction tube is inserted, and a cylindrical elastic member is hermetically attached between the opening edge of the insertion port and the upper portion of the gas introduction tube. A lid is formed so as to be movable up and down, and a partition plate divided into a plurality of parts is provided between the front end of the gas introduction pipe and the outer peripheral wall of the chamber body to partition the chamber vertically A reaction chamber is formed on the susceptor side, a susceptor cover divided into a plurality of parts is provided on the surface of the susceptor on the reaction chamber side, and the chamber is accommodated in a film formation chamber connected with a glove box through a partition door The partition plate and the susceptor cover formed separately in the chamber can be taken out from the film formation chamber into the glove box with the chamber lid being separated from the chamber body, and the glove box A vapor phase growth apparatus characterized in that it can be mounted in the chamber from the inside.

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