JP2007258516A - Vapor phase epitaxy device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase epitaxy device capable of preventing a corrosion of a flow channel caused by an attachment which has a strong corrosion action to substantially decrease an exchange frequency of the flow channel. <P>SOLUTION: The vapor phase epitaxy device grows the vapor phase of a thin film on the surface of a substrate by inserting a susceptor 12 with the substrate 11 mounted into an opening part 14 formed in the flow channel 13, and supplying a vapor phase material in the flow channel 13 with the substrate 11 heated. A concave part 14a is formed in a periphery of the opening part 14, and a cover member 17 is removably fixed to the concave part 14a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus, and more particularly to a vapor phase growth apparatus that performs vapor phase growth by inserting a susceptor on which a substrate is placed into an opening formed in a flow channel.

  As a vapor phase growth apparatus for manufacturing thin films such as compound semiconductors used in light emitting diode and laser diode light emitting devices, the upper part of the susceptor with the substrate placed on the top is inserted into the opening formed in the bottom wall of the flow channel Then, while rotating the susceptor, the susceptor is heated by a heater disposed in a reflector that covers a lower outer periphery of the susceptor, the substrate is heated through the susceptor, and a vapor phase raw material is supplied into the flow channel. There is known a vapor phase growth apparatus for depositing a thin film on the substrate. The susceptor is generally formed in a circular shape in plan view, and the opening of the flow channel bottom wall is formed in a circular shape into which the susceptor can be inserted and the susceptor can rotate.

Since the susceptor during vapor phase growth is rotated for the purpose of averaging the thickness of the thin film on the substrate, it rotates between the inner peripheral surface of the circular opening of the bottom wall of the flow channel and the outer peripheral surface of the susceptor. A gap with a certain margin is provided so that the susceptor does not contact the flow channel (see, for example, Patent Document 1).
JP-A-5-283339

  When a GaN-based compound semiconductor thin film is grown using the vapor phase growth apparatus as described above, trimethylgallium (TMG), which is a raw material, reacts with ammonia in the gap between the susceptor and the opening to generate Ga and GaN. And these reaction products adhere to an opening part. In particular, since the inner peripheral surface of the opening is heated to a high temperature by the susceptor, reaction products easily adhere to it, and many reaction products adhere to the corners between the inner peripheral surface of the opening and the peripheral upper surface. To do.

  If vapor phase growth is repeated with Ga or GaN with strong reducing power attached, the quartz glass forming the flow channel is eroded and begins to chip at the corners and inside of the opening, and flows from the chipped portion. Gas in the channel leaks to the outside. For this reason, the bottom plate (plate) of the flow channel had to be replaced periodically.

  Accordingly, an object of the present invention is to provide a vapor phase growth apparatus capable of preventing the flow channel from being eroded by deposits having a strong erosive force and greatly reducing the frequency of replacement of the flow channel.

  In order to achieve the above object, the vapor phase growth apparatus of the present invention inserts a susceptor on which a substrate is placed into an opening formed in the flow channel, and supplies the vapor phase raw material into the flow channel in a state where the substrate is heated. In the vapor phase growth apparatus for vapor-depositing a thin film on the substrate surface by supplying, a concave surface portion is formed around the opening, and a cover member is detachably attached to the concave surface portion. Yes.

  Furthermore, in the vapor phase growth apparatus of the present invention, a susceptor on which a substrate is placed is inserted into an opening formed in the bottom wall of the flow channel, and the vapor phase material is supplied into the flow channel while the substrate is heated. Thus, the vapor phase growth apparatus for vapor-depositing a thin film on the substrate surface includes a ring-shaped cover member that is detachably attached to the opening, and the cover member can be inserted into the opening. A cylindrical portion having a diameter, and a flange portion projecting from the upper end of the cylindrical portion to the outer periphery, and on the upper peripheral edge of the opening portion, the flange portion has the same depth as the thickness of the flange portion. A concave surface portion having an inner diameter corresponding to the outer diameter is provided.

  According to the vapor phase growth apparatus of the present invention, Ga or GaN generated during vapor phase growth adheres to the cover member. Therefore, it is only necessary to replace the cover member, which is less expensive than the plate replacement of the flow channel. Reduction can be achieved. In addition, by preparing a plurality of cover members and performing a cleaning operation for periodically removing them to remove deposits, the progress of erosion can be delayed and the life of the cover members can be extended.

  FIG. 1 is a sectional front view of a vapor phase growth apparatus showing one embodiment of the present invention, and FIG. 2 is a plan view of a plate portion of the flow channel.

  In this vapor phase growth apparatus, a susceptor 12 on which a plurality of substrates 11 are mounted is inserted into an opening 14 formed in a bottom wall (plate) 13a of a flow channel 13, and the susceptor 12 is rotated while the susceptor 12 is rotated. The susceptor 12 is heated by a heater 16 disposed in a reflector 15 covering the outer periphery of the back surface of the substrate, the substrate 11 is heated through the susceptor 12, and a vapor phase raw material is supplied into the flow channel 13 to A thin film is vapor-phase grown on the upper surface.

  A cover member 17 that covers the inner peripheral surface and the peripheral upper surface of the opening 14 is attached to the opening 14 in a detachable state. The cover member 17 has an outer diameter that can be inserted into the opening 14, and has a cylindrical portion 17 a having an inner diameter larger than the outer diameter of the susceptor 12, and projects from the upper end portion of the cylindrical portion 17 a to the outer periphery. A concave portion having an inner diameter corresponding to the outer diameter of the flange portion 17b at the same depth as the thickness of the flange portion 17b. 14a is provided.

  The cover member 17 has a cylindrical shape when the flange portion 17b is fitted to the concave surface portion 14a and mounted on the opening portion 14, and the upper surfaces of the flange portion 17b and the cylindrical portion 17a are flush with the upper surface of the plate 13a. A gap is formed between the inner peripheral surface of the portion 17a and the outer peripheral surface of the susceptor 12 so as not to hinder the rotation of the susceptor 12.

  The axial length of the cylindrical portion 17a is formed longer than the thickness of the plate 13a, and when the cover member 17 is attached to the opening 14, the lower end of the cylindrical portion 17a is lower than the lower surface of the plate 13a. It is set so as to protrude downward and to be close to the upper surface of the reflector 15.

  The cover member 17 is preferably made of a material resistant to ammonia, hydrogen, an organic metal, and a decomposition product thereof. Specifically, quartz glass, aluminum oxide, silicon nitride, boron nitride, corrosion-resistant carbon, aluminum nitride A mixture of silicon nitride boron and the like is desirable. A high melting point metal such as tungsten or molybdenum can also be used.

  When the GaN compound semiconductor thin film is vapor-phase grown using this vapor phase growth apparatus, a sapphire substrate is used as the substrate 11 and is heated to a high temperature state of 1000 ° C. or higher by the heater 16. Further, as a vapor phase raw material, trimethylgallium (TMG), which is an organic metal, and ammonia are used at a predetermined ratio, and the raw material gas adjusted to a predetermined flow rate is a flow channel 13 using hydrogen or nitrogen at a predetermined flow rate as a carrier gas. Introduced in.

  The source gas introduced into the flow channel 13 reacts by being heated from the high-temperature substrate 11, and by this reaction, a GaN crystal film is vapor-phase grown on the substrate surface. The source gas that has not contributed to the vapor phase growth is discharged from the flow channel 13 along with the carrier gas, but a part of the reaction product (GaN) is part of the inner surface of the flow channel 13 that is a quartz glass part. It adheres to the cover member 17 and the like. At this time, a large amount of reaction product is attached to the cover member 17 in the vicinity of the corner portion from the inner peripheral surface to the upper surface of the cylindrical portion 17a.

  When the vapor phase growth of the GaN compound semiconductor thin film is repeated with the reaction product attached to the cover member 17, the inner portion of the cover member 17 is eroded by the reducing power of Ga and gradually begins to lack. In this case, if only the cover member 17 is replaced, the vapor phase growth can be continued as it is, and there is no need to replace the flow channel 13 as in the conventional case.

  Also, a plurality of cover members 17 are prepared, and the cover member 17 is exchanged periodically, for example, every time of vapor phase growth or every plurality of vapor phase growths. By performing a cleaning operation for removing the attached reaction product, the cover member 17 can be regenerated and reused. By periodically performing such a cleaning operation, it is possible to suppress the erosion effect due to the adhesion of the reaction product and extend the useful life of the cover member.

  For example, if the vapor phase growth of the GaN compound semiconductor thin film is repeated with the reaction product attached, the inside of the cover member 17 starts to be eroded about several tens of times, but it is cleaned once or several times. By performing the operation, it is possible to withstand vapor phase growth of 100 times or more. Further, since the plate 13a of the flow channel 13 is hardly eroded by the reaction product, it is not necessary to replace it even if vapor phase growth is performed several hundred times.

  FIG. 3 is a cross-sectional front view of the main part showing another example of the shape of the cover member 17, FIG. 3 (A) shows the cover member 17 having the same thickness as the plate 13a, and FIG. FIGS. 3C and 3D show the cover member 17 in which the cylindrical portion is eliminated, and the cover member 17 divided and formed from different materials. For example, it is possible to reduce the cost by using a low-priced material for the part where erosion is likely to proceed. Also, since the method of contamination is different even in the cover member, it is necessary to replace part of the cover member temporarily. Even in such a case, it is possible to reduce the cost by selecting a cheap material in advance in a place that is easily damaged. Furthermore, the temperature is controlled by the difference in the material, and for example, the portion where gas passes easily erodes, so by changing the temperature environment by changing the material of such a portion, it is possible to suppress the way of contamination. .

  FIG. 4 is a plan view of the main part showing another example of the shape of the cover member 17, and as shown in FIGS. 4A to 4G, the upper surface of the cover member 17 has various shapes. can do.

  FIG. 5 is a plan view of a main part showing still another example of the shape of the cover member 17, and the upstream side and the downstream side are formed asymmetrically as shown in FIGS. 5 (A) to (F). You can also

  By appropriately selecting such top surface shapes, it is possible to adjust the temperature distribution on the substrate surface and the gas temperature.

1 is a cross-sectional front view of a vapor phase growth apparatus showing an embodiment of the present invention. It is a top view of the plate part of a flow channel similarly. It is a cross-sectional front view of the principal part which shows the other example of a shape of a cover member. It is a top view of the principal part which similarly shows the other example of a shape of a cover member. It is a top view of the principal part which shows the other example of another shape of a cover member similarly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... Susceptor, 13 ... Flow channel, 13a ... Bottom wall (plate), 14 ... Opening part, 14a ... Concave part, 15 ... Reflector, 16 ... Heater, 17 ... Cover member, 17a ... Cylindrical part, 17b ... Flange

Claims (2)

  A susceptor on which a substrate is placed is inserted into an opening formed in the flow channel, and a gas phase raw material is supplied into the flow channel while the substrate is heated. In the phase growth apparatus, a concave surface portion is formed around the opening, and a cover member is detachably attached to the concave surface portion.   A susceptor on which a substrate is placed is inserted into an opening formed in the bottom wall of the flow channel, and a vapor phase material is supplied into the flow channel while the substrate is heated, whereby a thin film is deposited on the substrate surface. A vapor phase growth apparatus for growth includes a ring-shaped cover member that is detachably attached to the opening, and the cover member includes a cylindrical portion having an outer diameter that can be inserted into the opening, and the cylindrical shape. And a concave surface portion having an inner diameter corresponding to the outer diameter of the flange portion at the same depth as the thickness of the flange portion on the peripheral upper surface of the opening portion. A vapor phase growth apparatus characterized by comprising:

Images