JP2019196293A - Vapor growth apparatus - Google Patents

Abstract

To provide a technology related to a vapor growth apparatus of a compound semiconductor.SOLUTION: A vapor growth apparatus includes a reaction vessel. The vapor growth apparatus includes a wafer holder arranged in the reaction vessel. The vapor growth apparatus includes a first raw material gas supply pipe for supplying a first raw material gas to the reaction vessel. The vapor growth apparatus includes a second raw material gas supply pipe for supplying a second raw material gas to the reaction vessel, the second raw material gas reacting with the first raw material gas. The vapor growth apparatus includes a first heating part. A surface of an area close to a gas supply port of at least the first raw material gas supply pipe and the second raw material gas supply pipe is covered with a predetermined metal. The predetermined metal is a metal capable of decomposing the second raw material gas with a catalytic effect. The first heating part heats the surface of the predetermined metal to 800°C or more.SELECTED DRAWING: Figure 1

Description

  The present specification discloses a technique related to a vapor phase growth apparatus for a compound semiconductor.

  Construction of a low-cost manufacturing method for GaN substrates is required. The current GaN substrate is a single-wafer type that grows one by one, which is a cause of high cost. A related technique is disclosed in Patent Document 1.

JP 2002-316892 A

  If long crystal growth of GaN becomes possible, a plurality of wafers can be generated from one long crystal, and the substrate manufacturing cost can be reduced. However, it is difficult to grow long crystals of GaN. One of the factors is that abnormal growth occurs as a result of gas tube clogging or gas flow change due to the deposition of GaN polycrystals at the source gas supply port.

  The present specification discloses a vapor phase growth apparatus. This vapor phase growth apparatus includes a reaction vessel. The vapor phase growth apparatus includes a wafer holder disposed in a reaction vessel. The vapor phase growth apparatus includes a first source gas supply pipe that supplies a first source gas into the reaction vessel. The vapor phase growth apparatus includes a second source gas supply pipe that supplies a second source gas that reacts with the first source gas into the reaction vessel. The vapor phase growth apparatus includes a first heating unit. The surface of the region in the vicinity of the gas supply port of at least one of the first source gas supply pipe and the second source gas supply pipe is covered with a predetermined metal. The predetermined metal is a metal that can decompose the second source gas by a catalytic effect. The first heating unit heats the surface of the predetermined metal to 800 ° C. or higher.

  In the vapor phase growth apparatus of the present specification, the catalytic effect of the predetermined metal can be enhanced by heating the surface of the predetermined metal to 800 ° C. or higher. Therefore, the second source gas can be decomposed on the surface of the region near the gas supply port. Thereby, precipitation of the GaN polycrystal to the area | region of the vicinity of a gas supply port can be suppressed.

  A shower head in which a plurality of gas supply ports of the first source gas supply pipe and a plurality of gas supply ports of the second source gas supply pipe are arranged may be further provided. At least the gas supply port side surface of the shower head may be covered with a predetermined metal.

  Gas supply ports may be arranged at the ends of the first source gas supply pipe and the second source gas supply pipe. The inner wall and the outer wall of the first source gas supply pipe may be covered with a predetermined metal in a region near the end of the first source gas supply pipe on the gas supply port side. The inner wall and the outer wall of the second source gas supply pipe may be covered with a predetermined metal in a region near the end of the second source gas supply pipe on the gas supply port side.

  The inner diameter of the second source gas supply pipe may be larger than the outer diameter of the first source gas supply pipe. The first source gas supply pipe may be disposed inside the second source gas supply pipe.

  The first source gas supply pipe and the second source gas supply pipe may form an integral common pipe. The first source gas and the second source gas may be supplied to an inlet located on the opposite side of the common pipe from the gas supply port. The inner wall of the common pipe may be covered with a predetermined metal over the entire length from the inlet to the gas supply port. You may further provide the 2nd heating part which heats a common pipe to 800 degreeC or more over the full length from an inlet_port | entrance to a gas supply port.

  You may provide the 3rd heating part which heats the temperature of the area | region between the gas supply port of a 1st source gas supply pipe and a 2nd source gas supply pipe, and a wafer holder to 500 degreeC or more.

  You may provide the 1st supply part which supplies 1st source gas to the inlet_port | entrance located in the other side of the gas supply port of a 1st source gas supply pipe | tube. You may provide the 2nd supply part which supplies 2nd source gas to the inlet located in the opposite side of the gas supply port of a 2nd source gas supply pipe | tube. The first supply unit and the second supply unit may supply the first source gas and the second source gas during a period in which the surface of the predetermined metal is 800 ° C. or higher.

  The first supply unit and the second supply unit may start supplying the first source gas and the second source gas after the surface of the predetermined metal is heated to 800 ° C. or higher by the first heating unit. The first heating unit may end the heating of the surface of the predetermined metal after the supply of the first source gas and the second source gas is stopped by the first supply unit and the second supply unit.

  The predetermined metal may include tungsten or tungsten-containing metal, tungsten or tungsten-containing metal oxide, tungsten or tungsten-containing metal carbide, tungsten or tungsten-containing metal nitride.

The first source gas may be a gas containing GaCl. The second source gas may be a gas containing NH ₃ .

It is the schematic sectional drawing which looked at the vapor phase growth apparatus concerning Example 1 from the side. It is the figure which looked at the sectional view in the II-II line from the perpendicular upper part. It is the schematic sectional drawing which looked at the vapor phase growth apparatus concerning Example 2 from the side. It is the schematic sectional drawing which looked at the vapor phase growth apparatus concerning Example 3 from the side. It is the schematic sectional drawing which looked at the vapor phase growth apparatus concerning Example 4 from the side. It is the schematic sectional drawing which looked at the shower head provided with the mixing chamber from the side.

<Configuration of vapor phase growth apparatus>
FIG. 1 shows a schematic cross-sectional view of a vapor phase growth apparatus 1 according to the technique of this specification as viewed from the side. The vapor phase growth apparatus 1 is an example of an apparatus configuration for carrying out a HVPE (Halide Vapor Phase Epitaxy) method. The vapor phase growth apparatus 1 includes a reaction vessel 10. The reaction vessel 10 has a cylindrical shape. The reaction vessel 10 may be made of quartz. Inside the reaction vessel 10, a source gas supply unit 20 and a wafer holder 11 are arranged.

The structure of the source gas supply unit 20 will be described. The source gas supply unit 20 is a cylindrical member. The source gas supply unit 20 includes a cylindrical cover 24. A disc-shaped shower head 50 is disposed at the upper end of the cover 24. In the lower part of the source gas supply unit 20, an inlet of the HCl gas supply pipe 25 and an inlet of the second source gas supply pipe 22 are arranged. A first valve 61 is disposed at the inlet of the HCl gas supply pipe 25. The first valve 61 controls the supply of gas containing HCl. The outlet of the HCl gas supply pipe 25 is connected to the first source gas generation unit 41. The first source gas generation unit 41 stores metal gallium inside. The first source gas generation unit 41 is a part that generates a first source gas G1 containing GaCl. The first source gas supply pipe 21 is a pipe that supplies the first source gas G1. The inlet of the first source gas supply pipe 21 is connected to the first source gas generator 41. The outlet of the first source gas supply pipe 21 is connected to the shower head 50. A second valve 62 is disposed at the inlet of the second source gas supply pipe 22. The second valve 62 controls the supply of gas containing the second source gas G2. The second source gas G2 is a gas containing NH ₃ . The outlet of the second source gas supply pipe 22 is connected to the shower head 50.

  The first source gas supply pipe 21 and the second source gas supply pipe 22 are arranged to extend in the vertical direction (that is, the z-axis direction in FIG. 1). A partition wall 42 is disposed on the path of the first source gas supply pipe 21 and the second source gas supply pipe 22. The partition wall 42 is a quartz plate that extends horizontally in the cover 24. The space in the cover 24 is separated up and down by a partition wall 42. The partition wall 42 functions as a heat insulating material.

  The shower head 50 is a part for discharging the first source gas G 1 and the second source gas G 2 to the vicinity of the surface of the wafer 13. The first source gas G1 and the second source gas G2 discharged from the shower head 50 flow vertically upward in the reaction container 10 in the direction of the arrow Y1. The structure of the shower head 50 will be described with reference to FIG. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 as viewed from above. On the surface of the shower head 50, a plurality of first gas supply ports 51 for discharging the first source gas G1 and a plurality of second gas supply ports 52 for discharging the second source gas G2 are arranged. By discharging the first source gas G1 and the second source gas G2 from a large number of gas supply ports, the gas supply amount to the surface of the wafer 13 can be made uniform in the wafer plane. Therefore, it is possible to suppress the variation in the wafer surface of the grown GaN crystal film thickness.

A region where the first gas supply port 51 and the second gas supply port 52 are not formed on the surface of the shower head 50 is covered with a predetermined metal 53. In other words, the surface of the area in the vicinity of the first gas supply port 51 and the second gas supply port 52 is covered with the predetermined metal 53. The predetermined metal 53 is a metal that can decompose NH ₃ contained in the second source gas by a catalytic effect. The predetermined metal 53 may be composed of a metal plate having a thickness of several millimeters. The metal plate may have a plurality of holes corresponding to the positions and hole diameters of the first gas supply port 51 and the second gas supply port 52. In this embodiment, tungsten is used as the predetermined metal.

  Around the source gas supply unit 20, a gas exhaust pipe 23 for exhausting the gas in the reaction vessel 10 is configured. This will be described with reference to FIG. A cylindrical source gas supply unit 20 is further arranged inside the cylindrical reaction vessel 10. As a result, an annular gap is formed between the inner wall of the reaction vessel 10 and the outer wall of the cover 24 of the source gas supply unit 20. This annular gap functions as the gas exhaust pipe 23. That is, the gas exhaust pipe 23 is disposed so as to extend vertically downward (that is, in the −z-axis direction in FIG. 1) along the outer wall of the source gas supply unit 20 and the inner wall of the reaction vessel 10. Thereby, the gas exhaust pipe 23 can be disposed so as to surround the outer periphery of the shower head 50, the first source gas supply pipe 21, and the second source gas supply pipe 22.

  Further, the inlet 23 a (see FIG. 1) of the gas exhaust pipe 23 can be positioned on the side surface of the shower head 50. Therefore, as shown by an arrow Y2 in FIG. 1, the first source gas G1 and the second source gas G2 used for the GaN crystal growth on the surface of the wafer 13 are exhausted in the lateral direction of the shower head 50 and downward of the wafer 13. Can be made. An outlet 23 b of the gas exhaust pipe 23 is disposed at the lower end of the reaction vessel 10. The gas sucked from the inlet 23a of the gas exhaust pipe 23 is discharged from the outlet 23b to the vent line.

  The wafer holder 11 is disposed in the reaction container 10. The wafer holder 11 includes a wafer holding unit 12 on the lower surface. The wafer holding unit 12 holds the wafer 13 so that the surface of the wafer 13 is substantially vertically downward. Note that “substantially vertically downward” is not limited to an aspect in which the normal line of the wafer coincides with the vertically downward direction. This is a concept in which the normal of the wafer includes an inclination of up to 45 degrees with respect to the vertical downward direction. In this embodiment, tungsten is disposed on the surface of the wafer holder 11. Thereby, the effect which suppresses precipitation of the GaN polycrystal on the surface of the wafer holder 11 is acquired.

  The lower end of the rotating shaft 14 is connected to the upper part of the wafer holder 11. The upper end portion of the rotating shaft 14 protrudes outside the reaction vessel 10. The upper end of the rotating shaft 14 is connected to the drive mechanism 15. Thereby, the wafer holder 11 can be rotated and moved up and down in the reaction vessel 10.

  A specific gas supply pipe 16 is provided at the top of the reaction vessel 10. A specific gas G3 is supplied to the inlet of the specific gas supply pipe 16. As indicated by an arrow Y3 in FIG. 1, the specific gas G3 flows from above the wafer holder 11 vertically downward and is sucked into the inlet 23a of the gas exhaust pipe 23. Thereby, a downflow can be generated by the specific gas G3. The specific gas G3 is a gas that does not contain oxygen and does not react with the first source gas G1 and the second source gas G2. As a specific example, the specific gas G3 is a gas containing at least one of hydrogen, nitrogen, helium, neon, argon, and krypton.

  An upper heater 31 and a lower heater 32 are disposed outside the reaction vessel 10. A partition wall 42 is disposed in the vicinity of the boundary between the region H1 where the upper heater 31 is disposed and the region H2 where the lower heater 32 is disposed. The upper heater 31 is disposed so as to surround the areas R1 to R3 shown in FIG. The region R1 is a region including the wafer 13. The region R1 is a region where it is necessary to maintain a temperature (1050 ± 50 ° C.) sufficient for GaN crystal growth. The region R <b> 2 is a region between the gas supply port of the shower head 50 and the wafer holder 11. The region R2 is a region that needs to be maintained at 500 ° C. or higher so that GaCl in the source gas is not decomposed. The region R3 is a region including a predetermined metal 53 that covers the surface of the shower head 50. The region R3 is a region that needs to be maintained at 800 ° C. or higher in order to suppress the precipitation of GaN polycrystals.

  The lower heater 32 is disposed so as to surround the region R4. The region R4 is a region including the first source gas generation unit 41. The region R4 is a region that needs to be maintained at a temperature higher than that necessary for stable generation of GaCl (750 ° C.).

<Vapor phase growth method>
A method of performing vapor phase growth of a GaN layer on the wafer 13 by the HVPE method will be described. An example of the gas phase growth conditions is listed. The supply amount of GaCl in the first source gas G1 and NH ₃ in the second source gas G2 was set to a molar ratio of 1:20. The pressure in the reaction vessel 10 was 1000 hPa.

  In the first step, the upper heater 31 is turned on. Region R1 (wafer 13), region R2 (region between the gas supply port and wafer holder 11), and region R3 (predetermined metal 53) are heated to 1050 ± 50 ° C. As a result, the upper heater 31 can maintain all of the regions R1 to R3 at a required temperature or higher. Further, by turning on the lower heater 32, the region R4 (first source gas generation unit 41) is heated to 750 ° C.

  When the surface of the predetermined metal 53 becomes 800 ° C. or higher, the process proceeds to the second step. The transition timing to the second step may be determined by measuring the surface temperature of the predetermined metal 53 with various sensors. In the second step, the supply of the first source gas G1 and the second source gas G2 is started by opening the first valve 61 and the second valve 62. Thereby, vapor phase growth of the GaN layer can be performed on the wafer 13. When the vapor phase growth is completed, the process proceeds to the third step, and the first valve 61 and the second valve 62 are closed. The supply of the first source gas G1 and the second source gas G2 ends. Thereafter, the process proceeds to the fourth step, and the upper heater 31 and the lower heater 32 are turned off. Thereby, the heating of the surface of the predetermined metal 53 is completed.

<Effect>
In the HVPE method, it is difficult to grow a long crystal (also referred to as a thick film crystal) on the c-plane of GaN. This is because it is difficult to suppress the occurrence of abnormal growth. As an example of the cause of the abnormal growth, GaN polycrystals are deposited at the first gas supply port 51 and the second gas supply port 52 arranged on the surface of the shower head 50, thereby clogging the gas pipe and changing the gas flow. May occur. As a countermeasure, it is conceivable to cover the surface of the shower head 50 with a predetermined metal (for example, tungsten) capable of decomposing NH ₃ by a catalytic effect. However, in order to prevent the precipitation of GaN polycrystals, the present inventors do not only need to cover the surface of the showerhead 50 with a predetermined metal, and the surface temperature of the predetermined metal needs to be 800 ° C. or higher. I found it. This is because active hydrogen generated when NH ₃ is decomposed by the catalytic effect is considered to suppress the precipitation of GaN polycrystals. Further, it is considered that 800 ° C. or higher is necessary for the active hydrogen to react with the GaN polycrystal. Therefore, the vapor phase growth apparatus 1 according to the first embodiment includes an upper heater 31 surrounding the area R3 including the predetermined metal 53. Thereby, since the surface of the predetermined metal can be heated to 800 ° C. or higher, it is possible to suppress the precipitation of GaN polycrystals on the surface of the shower head 50.

  In the vapor phase growth method of Example 1, the supply of the first source gas G1 and the second source gas G2 is started in response to the surface of the predetermined metal 53 becoming 800 ° C. or higher (second step). In addition, after the first valve 61 and the second valve 62 are closed in the third step, the upper heater 31 is turned off in the fourth step. By the above flow, the first valve 61 and the second valve 62 are controlled so that “the first source gas G1 and the second source gas G2 are supplied while the surface of the predetermined metal 53 is 800 ° C. or higher”. Can do. Therefore, precipitation of GaN polycrystals on the surface of the showerhead 50 can be suppressed.

  FIG. 3 is a schematic sectional view of the vapor phase growth apparatus 201 according to the second embodiment as viewed from the side. The vapor phase growth apparatus 201 is an example of an apparatus configuration for performing the HVPE method. The vapor phase growth apparatus 201 includes a reaction vessel 210, a susceptor 211, a first source gas supply pipe 221, a second source gas supply pipe 222, and a gas exhaust pipe 271. The susceptor 211 is stored in the reaction vessel 210. A wafer 213 is held on the wafer holding surface of the susceptor 211.

  The reaction vessel 210 is connected to a first source gas supply pipe 221 that supplies a first source gas G1 and a second source gas supply pipe 222 that supplies a second source gas G2. The inner diameter D1 of the second source gas supply pipe 222 is larger than the outer diameter D2 of the first source gas supply pipe 221. A first source gas supply pipe 221 is disposed inside the second source gas supply pipe 222. A gap is formed between the outer wall of the first source gas supply pipe 221 and the inner wall of the second source gas supply pipe 222, and the second source gas G2 flows through the gap. The end region E1 of the first source gas supply pipe 221 and the second source gas supply pipe 222 functions as a gas supply port. In the vicinity of the end region E <b> 1, the inner wall and the outer wall of the first source gas supply pipe 221 and the second source gas supply pipe 222 are covered with a predetermined metal 253.

  A first source gas generation unit 241 is disposed on the path of the first source gas supply pipe 221. Metal gallium 243 is stored inside the first source gas generation unit 241. HCl gas is supplied to the inlet of the first source gas supply pipe 221, and the first source gas G1 is discharged from the gas supply port. The second source gas G2 is supplied to the inlet of the second source gas supply pipe 222, and the second source gas G2 is discharged from the gas supply port. A gas exhaust pipe 271 is connected to the reaction vessel 210. The source gas used for the vapor phase growth of GaN is discharged to the vent line via the gas exhaust pipe 271.

  A heater 231 is disposed on the outer periphery of the reaction vessel 210 so as to surround the susceptor 211. The heater 231 is a device that heats the wafer 213 by a hot wall method. As a result, the wafer 213 can be maintained at a temperature sufficient for GaN crystal growth (1050 ± 50 ° C.). Further, precipitation of by-products on the inner wall of the reaction vessel 210 can be suppressed. A heater 232 is disposed outside the reaction vessel 210 so as to surround the end region E1. Thereby, the predetermined metal 253 arrange | positioned at the edge part area | region E1 can be maintained at 800 degreeC or more. A heater 233 is disposed outside the second source gas supply pipe 222 so as to surround the first source gas generator 241. Thereby, in order to generate GaCl, the 1st source gas generating part 241 can be maintained at 750 ° C or more.

<Effect>
The vapor phase growth apparatus 201 according to the second embodiment includes a heater 232 that surrounds the periphery of a predetermined metal 253 disposed in the vicinity of the gas supply port (end region E1). Thereby, since the surface of the predetermined metal 253 can be heated to 800 ° C. or higher, it is possible to suppress the precipitation of GaN polycrystals at the gas supply port.

  FIG. 4 is a schematic cross-sectional view of the vapor phase growth apparatus 301 according to the third embodiment as viewed from the side. The vapor phase growth apparatus 301 according to the third embodiment positions the first source gas supply pipe 221 and the second source gas supply pipe 222 from the right side of the wafer with respect to the vapor phase growth apparatus 201 according to the second embodiment. It has a configuration that is moved upward. Further, the gas exhaust pipe 271 is moved from the left side of the wafer to the lower side. Since the same reference numerals are given to the same components as those of the vapor phase growth apparatus 201 of the second embodiment, detailed description thereof is omitted.

  Also in the vapor phase growth apparatus 301 of Example 3, the surface of the predetermined metal 253 can be heated to 800 ° C. or more by the heater 232. Therefore, it is possible to suppress the precipitation of GaN polycrystals at the gas supply port.

  FIG. 5 is a schematic sectional view of the vapor phase growth apparatus 401 according to the fourth embodiment as viewed from the side. The vapor phase growth apparatus 401 according to the fourth embodiment has a configuration including a common pipe 423 with respect to the vapor phase growth apparatus 201 according to the second embodiment. Since the same reference numerals are given to the same components as those of the vapor phase growth apparatus 201 of the second embodiment, detailed description thereof is omitted.

  The first source gas supply pipe 421 and the second source gas supply pipe 422 are connected to the common pipe 423 at the connection portion J1. In other words, the first source gas supply pipe 421 and the second source gas supply pipe 422 form an integrated common pipe 423. The end region E2 of the common pipe 423 functions as a gas supply port.

  In the common pipe 423, the positions of the inlets of the first source gas G1 and the second source gas G2 are defined as a position P1. The position of the gas supply port is defined as position P2. A region extending over the entire length from the position P1 to the position P2 is defined as a region R11. The common tube 423 has an inner wall covered with a predetermined metal 453 over the entire region including the region R11. Further, the inner wall and the outer wall of the common pipe 423 are covered with a predetermined metal 453 in the vicinity of the end region E2.

  The first source gas G1 is supplied to the inlet of the first source gas supply pipe 421, and the second source gas G2 is supplied to the inlet of the second source gas supply pipe 422. The first source gas G1 and the second source gas G2 are mixed inside the common pipe 423, and the mixed gas is discharged from the gas supply port of the common pipe 423.

  Heaters 432 and 433 are arranged so as to surround the common pipe 423 over the entire length of the region R11. Thereby, the predetermined metal 453 can be maintained at 800 ° C. or higher over the entire region including the region R11.

<Effect>
In the vapor phase growth apparatus 401 of Example 4, the first source gas G1 and the second source gas G2 can be mixed using the region R11 from the position P1 to the position P2 of the common pipe 423. Since a sufficient distance and time for mixing both gases can be taken, the gas can be discharged from the gas supply port of the common pipe 423 in a sufficiently mixed state. It is possible to grow a good GaN crystal at high speed, which is advantageous for cost reduction. Further, if sufficient distance and time for mixing both gases are taken, there is a risk that GaN polycrystal will precipitate on the inner wall of the common tube 423. Therefore, in the vapor phase growth apparatus 401 according to the fourth embodiment, the surface of the predetermined metal 453 on the inner wall of the common pipe 423 can be heated to 800 ° C. or more by the heaters 432 and 433 over the entire length of the common pipe 423. Precipitation of GaN polycrystals on the inner wall of the common tube 423 can be suppressed.

<Modification>
As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

Although tungsten has been described as an example of a metal capable of decomposing NH ₃ by a catalytic effect, the material is not limited to this material. Tungsten oxide (WOx), tungsten carbide (WCx), tungsten nitride (WNx), and the like can also be used. Metals containing tungsten (tungsten alloys) and oxides, carbides, and nitrides thereof can also be used. Other metals such as ruthenium, iridium, platinum, molybdenum, palladium, rhodium, iron, nickel, rhenium, etc. can also be used. In addition, oxides, carbides, nitrides of these metals, alloys containing these metals, and the like can also be used.

  The structure of the shower head is not limited to the structure shown in the first embodiment. For example, a mode in which a mixed gas in which the first source gas G1 and the second source gas G2 are mixed may be discharged from the shower head. FIG. 6 shows a schematic cross-sectional view of a shower head 50 including a mixing chamber 54 that generates a mixed gas as viewed from the side. A first gas supply port 51 and a second gas supply port 52 of the shower head 50 are connected to the lower part of the mixing chamber 54. A plurality of gas supply ports 55 are arranged in the upper part of the mixing chamber 54. The inner wall and the outer wall of the mixing chamber 54 are covered with a predetermined metal 56. The first source gas G1 and the second source gas G2 are mixed inside the mixing chamber 54, and the mixed gas Gm is discharged from the gas supply port 55. Explain the effect. Since the mixed gas Gm can be discharged from the gas supply port 55 of the mixing chamber 54, the V / III ratio in the raw material gas supplied to the wafer can be made uniform. A uniform GaN crystal can be grown. In addition, since the V / III ratio can be increased, the growth rate of the GaN crystal can be increased. Further, when the mixing chamber 54 is not provided, it is necessary to secure a certain distance between the gas supply port and the wafer surface in order to sufficiently mix the first source gas G1 and the second source gas G2. However, in the structure of FIG. 6 including the mixing chamber 54, the gas supply port and the wafer surface can be brought closer to each other, so that the growth rate of the GaN crystal is increased and the raw material efficiency is increased to suppress the gas consumption. It becomes possible to do. Moreover, the heater 31 (refer FIG. 1) is arrange | positioned so that the mixing chamber 54 may be surrounded. Thereby, the predetermined metal 56 can be maintained at 800 ° C. or higher over the entire mixing chamber 54. Precipitation of GaN polycrystals on the inner wall and outer wall of the mixing chamber 54 can be suppressed.

  In the first embodiment, the surface of the shower head 50 is covered with the predetermined metal 53. However, the present invention is not limited to this configuration, and the side surface of the shower head 50 may be covered with the predetermined metal 53. In Example 2-4, although the aspect which covers the inner wall and outer wall near the edge part of a gas supply pipe with a predetermined metal was demonstrated, it is not restricted to this aspect. The gas supply pipe itself may be formed of a material containing a predetermined metal.

  In the present embodiment, the mode in which the gas supply ports of both the first source gas supply pipe and the second source gas supply pipe are covered with the predetermined metal has been described, but the present invention is not limited to this mode. The surface of the area | region near the gas supply port of at least one gas supply pipe should just be covered with the predetermined metal. For example, in the structure in which the first source gas supply pipe 221 is arranged inside the second source gas supply pipe 222 as in the second embodiment (FIG. 3) and the third embodiment (FIG. 4), the first source material is provided. GaN polycrystal is likely to be deposited in the vicinity of the supply port of the gas supply pipe 221. Therefore, only the inner wall and the outer wall of the supply port of the first source gas supply pipe 221 may be covered with the predetermined metal 253. Conversely, only the inner wall and the outer wall of the supply port of the second source gas supply pipe 222 may be covered with the predetermined metal 253.

  In the first embodiment, the aspect in which the area around the regions R1 to R3 is surrounded by the upper heater 31 has been described. However, the upper heater 31 may be divided into two or more. Thereby, the temperature of area | region R1-R3 can be controlled separately.

  The temperature sufficient for GaN crystal growth was described as 1050 ± 50 ° C. Further, it has been described that the temperature necessary for the generation of GaCl is 750 ° C. or higher. However, these temperatures are exemplary. For example, the temperature sufficient for GaN crystal growth may be in the range of 1050 ° C. ± 100 ° C.

Although the case where the first source gas G1 is a gas containing GaCl has been described, it is not limited to this form. The first source gas G1 may be any gas having any chemical composition as long as it contains Ga. For example, the first source gas G1 may be a gas containing trichloride Ga (GaCl ₃ ). In this case, a growth temperature of about 1300 ° C. may be used. A GaN crystal may be grown on the N plane (-c plane). This makes it possible to enlarge the GaN crystal surface with growth.

  The number and arrangement of the first source gas supply pipes and the second source gas supply pipes described in this specification are merely examples, and are not limited to this form.

The technique described in this specification can be applied not only to the HVPE method but also to various growth methods. For example, it can be applied to a MOVPE (Metal Organic Vapor Phase Epitaxy) method. In this case, trimethylgallium (Ga (CH ₃ ) ₃ )) or the like may be used as the first source gas G1.

The technique described in this specification is applicable not only to GaN but also to crystal growth of various compound semiconductors. For example, it can be applied to the growth of GaAs crystals. In this case, arsine (AsH ₅ ) may be used as the second source gas G2.

The first raw material gas G1, the second source gas G2, may be flowed together with a carrier gas such as _{H 2} or _{N 2.}

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

  The upper heater 31, the heater 232, and the heater 432 are an example of a first heating unit. The upper heater 31 is an example of a third heating unit. The first valve 61 is an example of a first supply unit. The second valve 62 is an example of a second supply unit.

  DESCRIPTION OF SYMBOLS 1: Vapor growth apparatus 10: Reaction container 11: Wafer holder 21,221,421: 1st source gas supply pipe 22,222,422: 2nd source gas supply pipe 23: Gas exhaust pipe 31: Upper heater 32: Lower heater 41: First source gas generation unit 50: Shower head 53, 253, 453: Predetermined metal 231, 232, 233, 432, 433: Heater

Claims (10)

A reaction vessel;
A wafer holder disposed in the reaction vessel;
A first source gas supply pipe for supplying a first source gas into the reaction vessel;
A second source gas supply pipe for supplying a second source gas that reacts with the first source gas into the reaction vessel;
A first heating unit;
With
A surface of a region in the vicinity of at least one gas supply port of the first source gas supply pipe and the second source gas supply pipe is covered with a predetermined metal;
The predetermined metal is a metal capable of decomposing the second source gas by a catalytic effect,
The first heating unit heats the surface of the predetermined metal to 800 ° C. or higher, and is a compound semiconductor vapor phase growth apparatus. A shower head in which a plurality of gas supply ports of the first source gas supply pipe and a plurality of gas supply ports of the second source gas supply pipe are arranged;
The vapor phase growth apparatus according to claim 1, wherein at least a surface of the shower head on the gas supply port side is covered with the predetermined metal. The gas supply port is disposed at an end of the first source gas supply pipe and the second source gas supply pipe;
An inner wall and an outer wall of the first source gas supply pipe are covered with the predetermined metal in a region near the end of the first source gas supply pipe on the gas supply port side;
2. The vapor phase growth according to claim 1, wherein an inner wall and an outer wall of the second source gas supply pipe are covered with the predetermined metal in a region near an end of the second source gas supply pipe on the gas supply port side. apparatus. The inner diameter of the second source gas supply pipe is larger than the outer diameter of the first source gas supply pipe,
The vapor phase growth apparatus according to claim 3, wherein the first source gas supply pipe is disposed inside the second source gas supply pipe. The first source gas supply pipe and the second source gas supply pipe form an integral common pipe,
The first source gas and the second source gas are supplied to an inlet located on the opposite side of the gas supply port of the common pipe,
The common pipe has an inner wall covered with the predetermined metal over the entire length from the inlet to the gas supply port,
2. The vapor phase growth apparatus according to claim 1, further comprising a second heating unit configured to heat the common pipe to 800 ° C. or more over the entire length from the inlet to the gas supply port.   6. The apparatus according to claim 1, further comprising a third heating unit that heats a temperature of a region between the gas supply port of the first source gas supply pipe and the second source gas supply pipe and the wafer holder to 500 ° C. or more. The vapor phase growth apparatus of any one. A first supply unit for supplying the first source gas to an inlet located on the opposite side of the gas supply port of the first source gas supply pipe;
A second supply unit for supplying the second source gas to an inlet located on the opposite side of the gas supply port of the second source gas supply pipe;
With
The said 1st supply part and the said 2nd supply part supply any 1 item | term of the said 1st source gas and the said 2nd source gas during the period when the surface of the said predetermined metal is 800 degreeC or more. The vapor phase growth apparatus according to item. The first supply unit and the second supply unit start supplying the first source gas and the second source gas after the surface of the predetermined metal is heated to 800 ° C. or more by the first heating unit,
The first heating unit finishes heating the surface of the predetermined metal after the supply of the first source gas and the second source gas is stopped by the first supply unit and the second supply unit. Item 8. The vapor phase growth apparatus according to Item 7.   The said predetermined metal includes any one of tungsten or a metal containing tungsten, an oxide of tungsten or a metal containing tungsten, a carbide of tungsten or a metal containing tungsten, or a nitride of tungsten or a metal containing tungsten. The vapor phase growth apparatus according to claim 1. The first source gas is a gas containing GaCl;
The vapor phase growth apparatus according to any one of claims 1 to 9, wherein the second source gas is a gas containing NH ₃ .

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