JP2009194045A - Vapor phase epitaxy device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a material gas or a reaction product from leaking from a front face to a rear face of a susceptor, and to prevent an inert gas from leaking from the rear face to the front face of the susceptor in a simple structure. <P>SOLUTION: A plurality of substrate holding members 14 are rotatably provided along a circumference of the susceptor 13, and a fixed gear member 26 having an internal gear 26a engaging with an external gear 14b provided along a circumference of the member 14 is provided. A bottom plate 13c covering a lower part of the members 14 is provided on the susceptor 13, and in addition, the upper surface of the circumference of the bottom plate 13c is brought in proximity to a lower part of the fixed gear member 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus, and more particularly to a vapor phase growth apparatus provided with a mechanism for rotating and revolving a substrate on a susceptor.

The substrate held on the susceptor in the chamber is heated to a predetermined temperature by a heating means, and a source gas is supplied into the chamber to deposit a thin film on the substrate surface. The susceptor is rotated and the susceptor is rotated. A self-revolving type equipped with a self-revolving mechanism that allows a thin film to be uniformly formed on a plurality of substrates by rotating the substrate holding member that holds the substrate with rotation of the substrate and revolving the substrate during film formation. Vapor phase growth apparatuses are known. In such a self-revolving mechanism, an external gear is provided on the outer peripheral portion of the substrate holding member, and a fixed gear member having an internal gear engaged with the external gear is provided on the outer peripheral position of the susceptor, and the substrate is held as the susceptor rotates. The members are formed so as to rotate and revolve, and a rolling member (bearing) is interposed between the susceptor and the substrate holding member so that the substrate holding member rotates smoothly (see, for example, Patent Document 1). ). In some cases, a guide member for guiding the rolling member is provided between the susceptor and the rolling member (see, for example, Patent Document 2).
JP 2004-55636 A JP 2007-243060 A

  However, in the above-mentioned self-revolving vapor phase growth apparatus, the raw material gas and reaction product introduced from the external gear and the internal gear to the surface side of the susceptor leak to the back surface side of the susceptor, Inert gas introduced into the susceptor sometimes leaked to the surface side. For this reason, the impurity concentration increases on the susceptor surface side and crystallinity may decrease, resulting in a decrease in composition uniformity, film thickness uniformity, and reproducibility. As a result, the components such as the heating means may be corroded. Furthermore, if the surface on the heating means side of the substrate holding member is exposed, the exposed surface is likely to be altered by reaction with the raw material gas and the reaction product, resulting in a change in emissivity and a change in heat transfer amount. It was a cause of changes over time.

  In addition, when a large cylindrical susceptor as described in Patent Document 1 is used, it is difficult to efficiently transfer heat from the heating means to the substrate because of its large heat capacity, and the temperature rise and fall during film formation is difficult. In repetitive gallium nitride film formation, it takes time for the temperature to stabilize, and there is a risk that the film quality may deteriorate due to the boundary between the films.

  Accordingly, the present invention provides a vapor phase growth apparatus capable of preventing leakage of raw material gas and reaction products from the susceptor surface side to the back surface side and leakage of inert gas from the susceptor back surface side to the surface side with a simple structure. The purpose is to provide.

  In order to achieve the above object, the present invention provides a disk-shaped susceptor rotatably provided in a chamber, a plurality of disk-shaped substrate holding members rotatably provided on the outer periphery of the susceptor, and the substrate holding A fixed gear member having an internal gear that meshes with an external gear provided on the outer periphery of the member, a source gas introduction portion provided on the susceptor surface side of the chamber, and a non-circular member provided on the susceptor back side of the chamber. A rotation and revolution provided with an active gas introduction part, an exhaust part provided on each of the anti-raw material gas introduction part side and the anti-inert gas introduction part side of the chamber, and a heating means provided on the susceptor back side of the chamber In the vapor phase growth apparatus having a mechanism, the susceptor has a bottom plate that covers a lower portion of the substrate holding member, and an outer peripheral upper surface of the bottom plate is brought close to the lower portion of the fixed gear member. Characterized, it is preferable that the thickness of the bottom plate of the bottom and the susceptor of the substrate holding member to 10mm or less, respectively. Further, an inert gas introduction path for introducing an inert gas from the inside of the susceptor to the bottom surface portion of the substrate holding member is provided, and a flow rate adjustment for adjusting the flow rate of the inert gas introduced into the inert gas introduction path Means can also be provided.

  According to the vapor phase growth apparatus of the present invention, the raw material gas introduced into the surface side of the susceptor leaks from the meshing part of the external gear and the internal gear or the part of the rolling member to the back side of the susceptor, or the susceptor It is possible to prevent the inert gas introduced into the rear surface side of the susceptor from leaking to the front surface side. Thereby, an increase in impurity concentration on the susceptor surface side can be prevented, crystallinity is improved, and composition uniformity, film thickness uniformity, and reproducibility are improved. Further, on the back surface side of the susceptor, it is possible to prevent the component parts such as the heating means from being corroded by the raw material gas or particles, and the part replacement cycle can be extended.

  Furthermore, by reducing the thickness of the substrate holding member and the bottom plate of the receiving recess to 10 mm or less and keeping the thickness thin, the thermal conductivity is reduced even if the substrate holding member is not exposed to the heating means. The heat from the heating means can be efficiently transmitted to the substrate. In particular, even when the temperature rise / fall is repeated during film formation, such as gallium nitride film formation, the heat capacity of the susceptor is small, so that a rapid temperature increase / decrease rate and stability can be obtained. Can be formed.

  Further, the durability of the substrate holding member can be improved by introducing and purging an inert gas into the bottom surface portion of the substrate holding member. Furthermore, by controlling the flow rate of the inert gas, the temperature of the substrate can be controlled, and the surface temperature difference derived from the manufacturing error of the substrate holding member and the material unevenness can be reduced.

  FIG. 1 is a sectional view of a vapor phase growth apparatus showing a first embodiment of the present invention. In the vapor phase growth apparatus 11 shown in this embodiment, a disk-shaped susceptor 13 is rotatably provided in a flat cylindrical chamber 12, and a plurality of substrate holding members 14 are rotatably provided on the outer periphery of the susceptor 13. The susceptor 13 is supported by a rotating shaft 15 that penetrates the bottom surface of the chamber 12. A heater 16 and a thermometer 17 are provided below the chamber 12, and a reflector 18 is provided around the heater 16. In addition, a source gas introduction part 19 is provided in the central part on the susceptor surface side of the chamber 12, an exhaust part 20 is provided in the outer peripheral part, and an inert gas introduction part 21 is provided around the rotating shaft 15. An inert gas lead-out part 22 communicating with the exhaust part 20 is provided on the outer periphery of the reflector 18.

  On the outer peripheral portion of the upper surface of the susceptor 13, receiving recesses 13 a having a circular shape in plan view for receiving the substrate holding member 14 are provided at equal intervals in the circumferential direction. An opening 13b is provided on the outer periphery of the susceptor 13 of the housing recess 13a, and a ring-shaped groove 13d is provided on the outer periphery of the housing recess of the bottom plate 13c of the susceptor 13, and a bottom plate on the inner periphery of the groove 13d. A circular concave portion 13e is provided on the lower surface so that the thickness of the bottom plate 13c including the concave groove 13d is made as thin as possible, and the distance between the substrate holding member 14 and the bottom plate 13c is reduced.

  The substrate holding member 14 is formed in a disk shape, a substrate holding recess 14a for holding the substrate 23 is formed on the upper surface, and an external gear 14b is formed on the outer periphery of the lower portion. The substrate holding member 14 is rotatably accommodated in the accommodating recess 13a via a guide member 25 having a large number of balls 24 which are rolling members formed of carbon or ceramic.

  Further, a ring-shaped fixed gear member 26 having an internal gear 26a meshing with the external gear 14b of the substrate holding member 14 protruding from the opening 13b is provided at the outer peripheral position of the susceptor 13, and below the internal gear 26a. Is formed so that the outer peripheral upper surface of the susceptor 13 is close.

Further, on the outer periphery of the upper surface of the substrate holding member 14 and the upper surface of the fixed gear member 26, a cover material for making the upper surface of the substrate 23 flush with the upper surface of the susceptor 13 and covering the upper surfaces of the external gear 14b and the internal gear 26a. 27 is provided.

  When the thin film is vapor-grown on the upper surface of the substrate 23 by the vapor phase growth apparatus 11 described above, when the susceptor 13 is rotated by rotating the rotating shaft 15 at a predetermined speed, the axis of the susceptor 13 is rotated by the rotation of the susceptor 13. When the external gear 14b of the substrate holding member 14 that revolves around the center meshes with the internal gear 26a of the fixed gear member 26, the substrate holding member 14 rotates about its axis, and the substrate 23 rotates and revolves. It becomes.

  On the other hand, in a state where the heater 16 is operated and the substrate 23 is heated to a predetermined temperature, for example, 1100 ° C., via the susceptor 13 and the substrate holding member 14, a predetermined source gas, for example, trimethylgallium and ammonia Is introduced to the upper surface side of the susceptor in the chamber 12 and discharged from the outer exhaust section 20, whereby a predetermined thin film can be uniformly deposited on the upper surfaces of the plurality of substrates 23. At the same time, a predetermined inert gas such as nitrogen gas is introduced into the space E below the susceptor 13 from the inert gas introduction part 21 and discharged from the exhaust part 20 to purge the space E.

  When the thin film is formed on the upper surface of the substrate 23 in this manner, the lower side of the substrate holding member 14 and the lower side of the internal gear 26a of the fixed gear member 26 are covered by the bottom plate 13c of the susceptor 13 and the upper surface of the outer peripheral portion. Source gas or reaction product introduced into the upper surface side of the susceptor 13 leaks from the gear 14b or the internal gear 26a to the lower surface side of the susceptor 13, or an inert gas introduced into the lower surface side of the susceptor 13 It is possible to prevent leakage to the upper surface side of the.

  This prevents an increase in impurity concentration on the upper surface side of the susceptor, thereby improving crystallinity and improving composition uniformity, film thickness uniformity, and reproducibility, thereby obtaining a high-quality thin film. it can. Further, on the lower surface side of the susceptor, it is possible to prevent the component parts such as the heater 16 from being corroded by the raw material gas and the reaction product, and the part replacement cycle can be extended.

  Further, in this embodiment, the substrate holding member 14 and the bottom plate 13c are brought close to each other while the circular concave portion 13e is provided on the bottom plate 13c of the susceptor 13 below the substrate holding member 14 to reduce the thickness of the bottom plate 13c. Therefore, even if the lower surface of the substrate holding member 14 is not exposed to the heater 16 side, it is possible to suppress a decrease in thermal conductivity, and to efficiently transfer the heat from the heater 16 to the substrate. The heat capacity of the bottom and the bottom plate 13c can be reduced.

  As described above, the thickness of the bottom plate 13c of the susceptor 13 and the thickness of the bottom portion of the substrate holding member 14 are each set to 10 mm or less, preferably 5 mm or less, while ensuring the necessary strength. Compared with the case where the thickness exceeds 10 mm, not only the heat transfer efficiency can be greatly improved, but also the heat capacity can be reduced, so that the temperature control of the substrate 23 can be performed efficiently.

  In particular, even when repeatedly raising and lowering the temperature during film formation as in the case of forming a gallium nitride-based thin film, the heat transfer efficiency is good and the heat capacity of the susceptor 13 is small. And a high quality thin film can be formed.

  In addition, by purging the space E below the susceptor 13 with an inert gas, it is possible to more reliably prevent the component parts such as the heater 16 from being corroded by the raw material gas and the reaction product, and extend the part replacement cycle. Can do.

  FIG. 2 is a diagram showing a second embodiment of the present invention, FIG. 3 is a diagram showing a third embodiment of the present invention, and FIGS. 4 and 5 are diagrams showing a fourth embodiment of the present invention. Components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the vapor phase growth apparatus shown in the second embodiment, the bottom plate 13c of the susceptor 13 is formed in a flat plate shape without providing the circular concave portion 13e in the first embodiment, and is a substrate holding member located on the inner peripheral side of the guide member 25 By projecting the bottom center part of 14 in a cylindrical shape downward, the bottom surface of the substrate holding member 14 and the top surface of the bottom plate 13c are brought close to each other.

  Thus, by making the bottom plate 13c of the susceptor 13 flat, leakage of gas above and below the susceptor 13 can be prevented and the substrate 23 can be efficiently heated.

In addition, since the bottom surface of the susceptor 13 has a smooth flat plate shape, the flow of the inert gas flowing below the susceptor 13 is not disturbed, and gas accumulation does not occur.

  In the vapor phase growth apparatus according to the third embodiment, an accommodation recess 13f provided in the susceptor 13 is formed by a through hole 13g that penetrates in the vertical direction and a bottom plate member 13h provided at the bottom of the through hole 13g. . A support protrusion 13i protruding in the inner peripheral direction is provided at the inner peripheral lower end of the through hole 13g, and the bottom plate member 13h made of a disk-shaped thin plate is placed on the support protrusion 13i.

  The bottom plate member 13h can be formed of the same material as the susceptor 13, and a material different from the susceptor 13 can be used as long as the material can be formed into a disk-shaped thin plate with good heat conduction. For example, a carbon surface coated with silicon carbide or the like can be used for the susceptor 13, and a silicon carbide molded product can be used for the bottom plate member 13 h.

  Thus, by forming the accommodating recess 13f with the through hole 13g and the bottom plate member 13h, leakage of gas above and below the susceptor 13 can be prevented and the substrate 23 can be efficiently heated. Further, the heating effect can be adjusted by changing the thickness of the bottom plate member 13h, and the surface temperature of each substrate 23 held by the plurality of substrate holding members 14 can be made uniform.

  The vapor phase growth apparatus according to the fourth embodiment forms a gas passage 28 using a pipe on the rotary shaft 15 and also forms a radial inert gas introduction passage 29 inside the susceptor 13. The inert gas supplied from 28 is introduced into the bottom surface portion of the substrate holding member 14 through the inert gas introduction path 29. Further, an orifice member 30 provided with a small through hole (orifice) 30a at the center can be attached and detached at the outer end of the inert gas introduction passage 29 as a flow rate adjusting means for adjusting the flow rate of the inert gas. And the flow rate of the inert gas introduced from each inert gas introduction path 29 to the bottom surface portion of each substrate holding member 14 can be adjusted by appropriately selecting the diameter of the orifice 30a.

  Thus, by introducing an inert gas into the bottom surface portion of the substrate holding member 14 and exhausting it from the outer periphery of the susceptor 13, the portion of the external gear 14 b of the substrate holding member 14, the portion of the guide member 25, and the fixed gear member 26. Even if source gas or particles enter the internal gear 26a portion, etc., these can be discharged quickly, preventing corrosion and wear of each component, and improving durability. Can do.

  Further, as the orifice member 30, a plurality of types having different orifices 30a are prepared, and the orifice member 30 having an optimum diameter is used according to the temperature state of the substrate 23 placed on the upper surface of the substrate holding member 14. Thus, the temperature difference between the plurality of substrates 23 can be reduced, and for example, it is possible to keep the variation within about 1 ° C. at 1100 ° C., so that the quality of the thin film can be made constant.

  In each of the above embodiments, the susceptor is housed in a flat cylindrical chamber, the substrate is held on the upper surface of the susceptor, and the source gas is introduced from the upper center of the susceptor and the active gas is introduced from the lower center (face) However, the present invention can also be applied to an apparatus having a structure in which the substrate is held on the lower surface of the susceptor (face-down). Further, the susceptor is accommodated in the flow channel, and the source gas is supplied from one of the flow channels. The present invention can also be applied to an apparatus having a structure in which it is introduced and exhausted to the other side.

It is sectional drawing of the vapor phase growth apparatus which shows the 1st form example of this invention. It is principal part sectional drawing of the vapor phase growth apparatus which shows the 2nd form example of this invention. It is principal part sectional drawing of the vapor phase growth apparatus which shows the 3rd form example of this invention. It is principal part sectional drawing of the vapor phase growth apparatus which shows the 4th example of this invention. It is VV sectional drawing of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Vapor phase growth apparatus, 12 ... Chamber, 13 ... Susceptor, 13a, 13f ... Housing recessed part, 13b ... Opening part, 13c ... Bottom plate, 13d ... Groove, 13e ... Circular recessed part, 13g ... Through-hole, 13h ... Bottom plate Member, 13i ... support protrusion, 14 ... substrate holding member, 14a ... substrate holding recess, 14b ... external gear, 15 ... rotating shaft, 16 ... heater, 17 ... thermometer, 18 ... reflector, 19 ... source gas introduction part, DESCRIPTION OF SYMBOLS 20 ... Exhaust part, 21 ... Inert gas introduction part, 22 ... Inert gas derivation part, 23 ... Board | substrate, 24 ... Ball, 25 ... Guide member, 26 ... Fixed gear member, 26a ... Internal gear, 27 ... Cover material, 28 ... Gas passage, 29 ... Inert gas introduction passage, 30 ... Orifice member, 30a ... Small passage hole

Claims (3)

A disk-shaped susceptor rotatably provided in the chamber, a plurality of disk-shaped substrate holding members rotatably provided on the outer periphery of the susceptor, and an external gear provided on the outer periphery of the substrate holding member; A fixed gear member having an internal gear to mesh with, a source gas introduction part provided on the susceptor surface side of the chamber, an inert gas introduction part provided on the susceptor back side of the chamber, and a reaction of the chamber In the vapor phase growth apparatus having a self-revolving mechanism comprising an exhaust part provided on each of the source gas introduction part side and the anti-inert gas introduction part side, and a heating means provided on the susceptor back side of the chamber, The susceptor has a bottom plate that covers a lower portion of the substrate holding member, and an outer peripheral upper surface of the bottom plate is brought close to the lower portion of the fixed gear member. 2. The vapor phase growth apparatus according to claim 1, wherein the thickness of the bottom portion of the substrate holding member and the bottom plate of the susceptor is 10 mm or less. A flow rate adjusting means for providing an inert gas introduction path for introducing an inert gas from the inside of the susceptor to the bottom surface portion of the substrate holding member, and for adjusting a flow rate of the inert gas introduced into the inert gas introduction path; 3. The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus is provided.

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