JP2008060369A - Vapor growth device, compound semiconductor film, and its growth method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor growth device of which efficiency in use of material gas is improved, along with a compound semiconductor film with less defects, and its growth method. <P>SOLUTION: In a vapor growth device 10, a turbulent flow is easy to occur between a supply opening 28 and a substrate W because of a throttling part 26a provided to the supply opening 28 of a supply pipe 24. Material gas G1 is effectively mixed with material gas G2 due to the turbulent flow for reaction on the substrate W. So the vapor growth device 10 is improved in use efficiency of the material gas G1 and G2 compared with a vapor growth device 10A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus, a compound semiconductor film, and a growth method thereof.

  Compound semiconductors such as GaN, GaAs, and InP are suitably used for light-emitting elements and high-speed electronic devices. A crystal made of such a compound semiconductor is usually grown on a substrate using a metal organic chemical vapor deposition method (MOCVD method) or a hydride vapor phase epitaxy method (HVPE method). In particular, when the HVPE method is used, a GaN single crystal can be grown at a high speed.

Examples of the vapor phase growth apparatus for performing the HVPE method include those described in Non-Patent Document 1. Such a vapor phase growth apparatus is also used when growing an AlN single crystal. An NH ₃ gas introduction tube for introducing ammonia (NH ₃ ) into the reaction tube, and aluminum trichloride (AlCl ₃ ) in the reaction tube. An AlCl ₃ gas introduction pipe to be introduced and a substrate support are provided. The growth of AlN using such a vapor phase growth apparatus is performed by the following procedure.
(1) Carrier gas (hydrogen gas, nitrogen gas) is introduced into the reaction tube, and the temperature is raised until the substrate support is about 1200 ° C.
(2) NH ₃ NH ₃ was introduced from the gas inlet, the temperature of the substrate support is held to stabilize.
(3) Introduce AlCl ₃ from the AlCl ₃ gas introduction tube and grow the AlN crystal film on the substrate until it reaches a predetermined thickness. At this time, NH ₃ and AlCl ₃ react on the substrate in the reaction tube to grow an AlN film.
(4) When the AlN film reaches a predetermined thickness, the introduction of AlCl ₃ is stopped, the carrier gas is allowed to flow, the heater is stopped, and the temperature of the reaction tube is lowered to room temperature. When the temperature is sufficiently lowered, the substrate on which the AlN film has grown on the surface inside the container is taken out.
T.A. Goto et al., JOURNAL OF MATERIAL SCIENCE 27 (1992) p. 247

However, in the above-mentioned vapor phase growth apparatus, since the mixing of NH ₃ gas and AlCl ₃ gas was insufficient, the utilization efficiency of the raw material gas was low.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vapor phase growth apparatus, a compound semiconductor film with few defects, and a method for growing the same, in which the utilization efficiency of the source gas is improved. .

  In order to solve the above-described problems, a vapor phase growth apparatus according to the present invention is inserted into a reaction tube for growing a compound semiconductor by mixing a first source gas and a second source gas, and the reaction tube. A first supply tube for supplying the first source gas into the reaction tube, a second supply tube connected to the reaction tube and supplying the second source gas into the reaction tube, A substrate holder for holding a substrate near a first supply port formed at an end located in the reaction tube of the one supply tube, and a portion where the outer wall of the first supply tube faces the inner wall of the reaction tube The first supply pipe and the reaction tube form a double tube structure, and the space formed between the outer wall of the first supply pipe and the inner wall of the reaction tube is the second raw material. A second supply pipe is connected to the reaction tube so as to provide a gas flow path, and the reaction tube in the first supply pipe is disposed in the reaction tube. A gas flow adjusting portion that swells toward the inner wall of the reaction tube so as to reduce the cross-sectional area of the flow path of the second source gas is provided at the end of the first supply tube. The opening area of the supply port is smaller than the cross-sectional area of the first supply pipe.

  In the vapor phase growth apparatus of the present invention, the second source gas supplied from the second supply port is retained by the gas flow adjusting unit provided at the end of the supply pipe on the first supply port side. Instead, it flows to the vicinity of the first supply port and reacts with the first source gas. At this time, since the opening area of the first supply port is smaller than the cross-sectional area of the supply pipe, the flow rate of the first source gas supplied from the first supply port is significantly increased. Thereby, turbulent flow is likely to occur, and the first source gas and the second source gas are effectively mixed between the end of the supply pipe and the substrate. Improvement is realized.

  In order to solve the above-described problem, a vapor phase growth apparatus according to the present invention is inserted into a reaction tube for growing a compound semiconductor by mixing a first source gas and a second source gas, and the reaction tube. A first supply pipe for supplying the first raw material gas into the reaction tube, and a second supply pipe connected to the reaction tube and for supplying the second raw material gas into the reaction tube; And a substrate holder for holding the substrate near the first supply port formed at the end located in the reaction tube of the first supply tube, the outer wall of the first supply tube facing the inner wall of the reaction tube Thus, the first supply pipe and the reaction tube form a double pipe structure, and the space formed between the outer wall of the first supply pipe and the inner wall of the reaction pipe is the second. The second supply pipe is connected to the reaction tube so as to provide a flow path for the raw material gas, and the reaction in the first supply pipe The end located inside is provided with a gas flow adjusting portion swelled toward the inner wall of the reaction tube so as to reduce the cross-sectional area of the flow path of the second source gas, and the first supply port The head portion is provided with a plurality of small holes.

  In the vapor phase growth apparatus according to the present invention, the first source gas supplied from the supply pipe is ejected from a small hole in the head portion of the first supply port, so that the first gas supplied from the supply pipe The flow rate is significantly increased. Thereby, turbulent flow is likely to occur, and the first source gas and the second source gas are effectively mixed between the end of the supply pipe and the substrate. Improvement is realized.

  The compound semiconductor film of the present invention is grown using the vapor phase growth apparatus of the present invention. Since the use of the vapor phase growth apparatus of the present invention can suppress the introduction of defects into the growth film, a compound semiconductor film with few defects can be obtained. Therefore, the formation of defects in the structure of a semiconductor element manufactured using the same is suppressed, and the occurrence of malfunction of the element is reduced. The “compound semiconductor film” in the present invention includes, in addition to the compound semiconductor film formed on the substrate, a compound semiconductor film cut out by thick bulk growth (for example, a semiconductor substrate). And

  In the compound semiconductor film growth method of the present invention, the compound semiconductor film is grown using the vapor phase growth apparatus of the present invention. In this compound semiconductor growth method, since the vapor phase growth apparatus of the present invention is used, the utilization efficiency of the source gas is increased and the introduction of defects into the growth film can be suppressed.

  According to the present invention, there are provided a vapor phase growth apparatus, a compound semiconductor film with few defects, and a growth method therefor, in which the utilization efficiency of the source gas is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

(First embodiment)
FIG. 1 is a diagram schematically showing a vapor phase growth apparatus according to the first embodiment. The vapor phase growth apparatus 10 shown in FIG. 1 is preferably a hydride vapor phase growth apparatus (HVPE apparatus), but may be a metal organic vapor phase growth apparatus (MOCVD apparatus). When the vapor phase growth apparatus 10 is an HVPE apparatus, a compound semiconductor can be grown at a high speed. As compound semiconductors to be grown, there are III-V compound semiconductors (for example, GaAs, InP, AlN, GaN, InN, AlGaN, InGaN, AlInGaN, etc.) and II-VI group compound semiconductors (ZnSe, ZnO, etc.).

The vapor phase growth apparatus 10 includes a substantially cylindrical reaction tube 12 for growing a compound semiconductor by mixing a first source gas G1 and a second source gas G2. The source gases G1 and G2 are appropriately selected according to the generated compound semiconductor. The source gas G1 preferably contains a group III element such as Ga, Al, In or the like, and the source gas G2 preferably contains a group V element such as As, P or N. These source gases G1 and G2 may be diluted with a carrier gas such as hydrogen (H ₂ ), nitrogen (N ₂ ), or argon (Ar) in order to adjust the gas flow rate. In one embodiment, the source gas G1 is H ₂ diluted AlCl ₃ and the source gas G2 is H ₂ diluted NH ₃ . In this case, an AlN single crystal is grown as a compound semiconductor by mixing the source gas G1 and the source gas G2.

  At one end (upstream end) 12 a of the reaction tube 12, a first supply tube 24 for supplying the source gas G 1 into the reaction tube 12 and a source gas G 2 for supplying the source gas G 2 into the reaction tube 12 are provided. A second supply pipe 16 is attached. The supply pipes 16 and 24 are connected in the reaction pipe 12.

  A substrate holder 14 that holds the substrate W horizontally in the reaction tube 12 is attached to the other end (downstream end) 12 b of the reaction tube 12. The substrate holder 14 holds the substrate W in the vicinity of the first supply port 28 formed at the end portion 26 located in the reaction tube 12 in the supply tube 24. The substrate W is accommodated in the reaction tube 12 and is, for example, a semiconductor substrate such as a silicon (Si) substrate, a sapphire substrate, a silicon carbide (SiC) substrate, a zinc oxide (ZnO) substrate, or a GaAs substrate. In FIG. 1, one substrate W is disposed as an example, but a plurality of substrates W may be disposed. In this case, the plurality of substrates W are respectively fixed to the plurality of substrate holders 14, and each substrate holder 14 is fixed to the inner surface of the reaction tube 12. The substrate holder 14 is preferably disposed so as to surround the tube axis of the reaction tube 12. In this case, the circular arrangement is preferable because the growth rate of the films on all the substrates becomes uniform. When a plurality of substrates W are arranged, the compound semiconductor film M (compound semiconductor) can be grown on each substrate W at the same time, so that productivity is further improved. Further, if a rotation mechanism is attached to the substrate holder 14 and the substrate is rotated during growth, the uniformity of the growth rate on the substrate surface is improved. When the mixed gas G4 of the source gas G1 and the source gas G2 reaches the substrate W, the compound semiconductor film M is grown on the substrate W. At the other end 12 b of the reaction tube 12, an exhaust port 40 located on the downstream side of the substrate W is formed.

  One end 25 of the supply pipe 24 is connected to a supply device 23 that generates the raw material gas G1. The other end 26 of the supply tube 24 is located in the reaction tube 12. The supply pipe 24 has an end portion 26 in which a first supply port 28 for supplying the source gas G <b> 1 into the reaction tube 12 is formed, and an end portion 25 located on the upstream side of the end portion 26. The inner shape of the supply pipe 24 is a substantially straight tubular shape from the end portion 26 to the end portion 25, and the flow passage cross-sectional area hardly changes, but the restriction provided at the supply port 28 of the end portion 26 is provided. The cross-sectional area (opening area) is small in the portion 26a. The flow rate of the raw material gas G1 supplied from the supply pipe 24 to the reaction pipe 12 is increased to a level exceeding, for example, 10 m / s by the throttle portion 26a. The throttle portion 26a is a ring-shaped portion that integrally protrudes from the inner wall of the supply pipe 24 toward the pipe axis. The supply pipe 24 is connected to the reaction tube 12 and forms a double tube structure with the reaction tube 12. That is, since the outer wall of the supply tube 24 has a portion facing the inner wall of the reaction tube 12, the reaction tube 12 and the supply tube 24 form a double tube structure. A substrate holder 14 holding the substrate W is disposed near the supply port at a position downstream of the supply port 28. In order to obtain a high growth rate on the substrate W, the distance between the supply port 28 and the substrate W (distance between the supply port 28 and the center point of the surface of the substrate W in the tube axis direction of the reaction tube 12) d1 It is preferably 0.2 to 5 times the diameter L of 12 (see FIG. 2).

  Here, with reference to FIG. 2, these preferable shapes when the reaction tube 12, the gas flow adjusting unit 32, and the supply tube 24 are substantially rotationally symmetric will be described in detail. FIG. 2 is a diagram schematically showing the main part of the vapor phase growth apparatus shown in FIG. The diameter of the supply port 28 is x, the diameter of the reaction tube 12 is L, the shortest distance between the outer periphery of the gas flow adjusting unit 32 and the inner wall of the reaction tube 12 is d, and the gas flow adjusting unit 32 formed near the supply port 28. The length in the flow direction of the first portion 32a in which the outer diameter increases is y, the length in the flow direction of the first portion 32a in which the outer diameter widens is m, and the length in the flow direction of the second portion 32b whose outer diameter decreases toward the supply port 28. Let l be l. A preferable relationship between these sizes is as follows. d is preferably from x / 4 to 20x. y is preferably 0 or more and less than (Lx) / 2. l is preferably 0 or more and 20x or less. m is preferably 0 or more and 20x or less. However, at least one of l and m is not zero. x is preferably 0.001L or more and 0.5L or less.

In the production tube 21, for example, a source boat 20 in which Al pellets are accommodated is installed. A gas G3 is introduced into the generation pipe 21 via the introduction pipe 18. When the gas G3 comes into contact with the Al pellets in the source boat 20 in the generation pipe 21, the source gas G1 is generated. For example, when hydrogen chloride (HCl) diluted with H ₂ is used as the gas G3 and Al pellets are stored in the source boat 20, AlCl ₃ diluted with H ₂ is generated as the source gas G1.

  The discharge port 29 of the supply pipe 16 is located upstream of the supply port 28 of the supply pipe 24. Therefore, the source gas G <b> 2 discharged from the discharge port 29 of the supply pipe 16 is supplied to the surface of the substrate W from between the end portion 26 of the supply pipe 24 and the reaction tube 12. That is, the supply pipe 16 is connected to the reaction pipe 12 so that a space SP formed between the outer wall of the supply pipe 24 and the inner wall of the reaction pipe 12 serves as a flow path for the source gas G2. Thus, a second supply port 30 for supplying the source gas G2 to the surface of the substrate W is formed between the end portion 26 of the supply tube 24 and the reaction tube 12. The supply port 30 surrounds the supply port 28 in an annular shape when viewed from the tube axis direction of the reaction tube 12.

  At the end portion 26 of the supply pipe 24, a gas flow adjusting portion 32 swelled outward is formed so as to narrow the cross section of the second supply port 30. That is, the gas flow adjusting unit 32 swells toward the inner wall of the reaction tube 12 in the vicinity of the supply port 28 of the supply tube 24 so as to reduce the cross-sectional area of the flow path of the source gas G2. The gas flow adjusting unit 32 has a first portion 32a having an outer periphery extending toward the supply port 28 (that is, toward a downstream side in a direction along the extending direction of the supply pipe), and an outer periphery toward the supply port 28. However, the second portion 32b may have either one of the first portion 32a and the second portion 32b. The second part 32b is located adjacent to the supply port 28 side from the first part 32a, and the gas flow adjusting part 32 as a whole has a spindle shape (or streamline). Therefore, the cross-sectional area of the flow path of the source gas G2 is once narrowed toward the downstream side at the position of the gas flow adjusting unit 32 and then widened thereafter. The second portion 32b has a flat tip surface 24a. In FIG. 1, the gas flow adjusting unit 32 has a cross-sectional shape formed in a straight line, but these may be curved, and the gas flow adjusting unit 32 may take a streamlined shape.

  It is preferable that a heater 22 b extending along the tube axis direction of the reaction tube 12 is provided around the reaction tube 12. The heater 22b is located downstream of the heater 22a. The heater 22a heats the source boat 20 and promotes the generation of the source gas G1. The heater 22b heats the substrate W and promotes the reaction between the source gas G1 and the source gas G2. Moreover, it is preferable that the outer periphery of the heater 22a and the heater 22b is covered with a heat insulating material.

  Here, an example of a method for growing a compound semiconductor using the vapor phase growth apparatus 10 will be described. First, a carrier gas (hydrogen gas, nitrogen gas, etc.) is introduced into the reaction tube 12 and the temperature is raised until the substrate holder 14 reaches about 1100 ° C., for example. Next, the source gas G2 is supplied from the supply pipe 16 into the reaction pipe 12 to stabilize the temperature of the substrate holder 14. Further, the source gas G1 is supplied into the reaction tube 12 from the supply tube 24, and the compound semiconductor film M is grown on the substrate W until it reaches a predetermined thickness. At this time, the source gas G1 and the source gas G2 react on the substrate W in the reaction tube 12. Subsequently, when the compound semiconductor film M reaches a predetermined thickness, the supply of the raw material gas G1 is stopped, the carrier gas is supplied, the heater is stopped, and the temperature of the reaction tube 12 is lowered to room temperature. When the temperature is sufficiently lowered, the substrate W on which the compound semiconductor film M has been grown is taken out from the reaction tube 12.

  In the vapor phase growth apparatus 10 of the present embodiment, the raw material gas G2 and the raw material gas G1 are mixed in the vicinity of the supply port 28. Since the opening area of the supply port 28 of the supply pipe 24 is smaller than the flow passage cross-sectional area of the supply pipe 24 by the throttle portion 26a, the raw material gas G1 is ejected from the supply port 28 at a high flow rate. . As a result, turbulent flow is generated between the supply port 28 and the substrate W, and mixing of the raw material gas G1 and the raw material gas G2 is promoted and effectively mixed by the turbulent flow.

  On the other hand, as in the vapor phase growth apparatus 10A shown in FIG. 3, when the throttle part 26a is not provided at the end part 26 of the supply pipe 24, the source gas G1 is not supplied at high speed, and diffusion-driven mixing and Become. Therefore, in such a vapor phase growth apparatus 10A, the effect that the mixing of the source gas G1 and the source gas G2 is promoted by turbulent flow cannot be obtained.

  As described in detail above, in the vapor phase growth apparatus 10 according to the present embodiment, turbulent flow is likely to occur between the supply port 28 and the substrate W due to the throttle portion 26 a provided in the supply port 28. Yes. The turbulent flow effectively mixes the source gas G1 and the source gas G2 and reacts on the substrate W, so that the vapor phase growth apparatus 10 has the source gas G1 and G2 in comparison with the vapor phase growth apparatus 10A. Usage efficiency is improved.

In addition, if a large amount of film is deposited at a place other than the substrate surface such as the inner wall of the reaction tube 12, these films become thick during the growth, float on the substrate surface, drop, and defects are introduced into the grown film M. Although the situation may occur, in the vapor phase growth apparatus 10 described above, the gas flow adjusting unit 32 makes it difficult for the film to grow on the inner wall of the reaction tube 12. Is also significantly suppressed.
(Second Embodiment)

  FIG. 4 is a diagram schematically showing a vapor phase growth apparatus according to the second embodiment. A vapor phase growth apparatus 10B shown in FIG. 4 has the same configuration as the vapor phase growth apparatus 10 except that a supply pipe 24A is provided instead of the supply pipe 24.

  The end portion 26 of the supply pipe 24A has a substantially uniform wall thickness, and has a shape that becomes wider toward the downstream side. Therefore, the flow path cross-sectional area of the source gas G1 increases as it goes downstream. Along with this, the supply port 30 in the vapor phase growth apparatus 10B becomes narrower toward the downstream side. Therefore, the flow path cross-sectional area of the source gas G2 becomes smaller toward the downstream side. The supply port 28 of the supply pipe 24 is blocked by the head portion 31. The head portion 31 is a plate-like portion arranged so as to be orthogonal to the tube axis of the supply tube 24, and a plurality of small holes 31a are provided along the thickness direction thereof. That is, the end portion 26 of the supply pipe 24A has a shower head structure.

  Therefore, the source gas G <b> 1 supplied from the supply pipe 24 </ b> A is ejected from the small hole 31 a of the head portion 31 to the reaction tube 12. The flow rate of the source gas G1 ejected from the supply pipe 24A is increased to a level exceeding, for example, 10 m / s by the head portion 31. Thereby, turbulent flow is likely to occur between the supply port 28 and the substrate W.

  That is, also in this vapor phase growth apparatus 10B, the raw material gas G1 and the raw material gas G2 are effectively mixed by the turbulent flow generated between the supply port 28 and the substrate W, as in the vapor phase growth apparatus 10, and the raw material gas The utilization efficiency of G1 and G2 is improved.

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment. In the embodiment described above, the shape of the reaction tube and the supply tube is a cylindrical tube having a substantially circular cross section perpendicular to the gas flow. For example, the same effect can be obtained even if the cross section is a polygonal tube such as a triangle or a rectangle. can get. Even in this case, the cross-sectional shape parallel to the gas flow of the gas flow adjusting unit is the same as described above, but the cross-sectional shape perpendicular to the gas flow is similar to the cross-sectional shape of the reaction tube and the supply tube. Become.

  Further, in the above description, the substrate and the substrate holder are arranged so that the substrate surface is parallel to the gas flow, but the same is true even if the substrate and the substrate holder are arranged so that the substrate surface is perpendicular to the gas flow. An effect is obtained. In this case, when arranging one board | substrate, it is preferable to arrange | position so that the center of a board | substrate may come on the tube axis | shaft of a reaction tube. A plurality of substrates may be arranged so as to surround the tube axis of the reaction tube.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

  Hereinafter, Examples 1 to 8 and Comparative Examples 1 to 4 will be described in detail.

(Example 1)
An AlN film was grown on the SiC substrate using the vapor phase growth apparatus 10 shown in FIGS. As the vapor phase growth apparatus 10, an apparatus having z of 1 mm, x of 10 mm, L of 100 mm, d of 10 mm, y of 2 mm, l of 50 mm, and m of 150 mm was used (see FIG. 2). The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 50 mm. After the SiC substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1100 ° C. Al pellets were used as the Al raw material. While the Al pellets placed on the quartz boat were heated to 500 ° C., HCl gas diluted with N ₂ gas was flowed to generate AlCl ₃ gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average AlCl ₃ partial pressure in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.03 atm.

  After the AlN crystal was grown for 30 hours under the above-described conditions, the SiC substrate with the AlN film grown on the surface was taken out from the reaction tube 12. Since the thickness of the AlN film was 1848 μm, the growth rate of the AlN crystal could be estimated as 160 μm / hr.

(Example 2)
An AlN film was grown in the same manner as in Example 1 except that l of the vapor phase growth apparatus 10 was set to 100 mm. As a result, since the thickness of the AlN film was 1742 μm, the growth rate of the AlN crystal could be estimated to be 140 μm / hr.

(Example 3)
A GaN film was grown on the sapphire substrate using the vapor phase growth apparatus 10 shown in FIGS. As the vapor phase growth apparatus 10, an apparatus having z of 1 mm, x of 10 mm, L of 100 mm, d of 10 mm, y of 2 mm, l of 150 mm, and m of 150 mm was used (see FIG. 2). The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the substrate surface was about 50 mm. After the sapphire substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1050 ° C. Ga melt was used as the Ga raw material. In a state where the Ga melt placed on the quartz boat was heated to 800 ° C., HCl gas diluted with H ₂ gas was flowed to generate GaCl gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average partial pressure of GaCl in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.01 atm.

  After the GaN crystal was grown for 30 hours under the above conditions, the substrate on which the GaN film was grown was taken out from the reaction tube 12. Since the film thickness of the GaN film was 3380 μm, the growth rate of the GaN crystal could be estimated as 350 μm / hr.

Example 4
An AlN film was grown in the same manner as in Example 1 except that l of the vapor phase growth apparatus 10 was set to 150 mm. As a result, since the film thickness of the AlN film was 1200 μm, the growth rate of the AlN crystal could be estimated to be 40 μm / hr.

(Example 5)
A GaN film was grown in the same manner as in Example 3 except that l of the vapor phase growth apparatus 10 was 20 mm and m was 0 mm. As a result, since the film thickness of the GaN film was 2730 μm, the growth rate of the GaN crystal could be estimated to be 91 μm / hr.

(Example 6)
A GaN film was grown in the same manner as in Example 3 except that l of the vapor phase growth apparatus 10 was 20 mm and m was 50 mm. As a result, since the film thickness of the GaN film was 4560 μm, the growth rate of the GaN crystal could be estimated to be 120 μm / hr.

(Example 7)
An AlN film was grown on the SiC substrate using the vapor phase growth apparatus 10B shown in FIG. As the vapor phase growth apparatus 10, the cross-sectional area of the supply port 28 is about 962mm ^2, the total cross-sectional area of the small holes 31a is used as approximately 30 mm ^2. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 100 mm. After the SiC substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1100 ° C. Al pellets were used as the Al raw material. While the Al pellets placed on the quartz boat 20 were heated to 500 ° C., HCl gas diluted with N ₂ gas was flowed to generate AlCl ₃ gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average AlCl ₃ partial pressure in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.03 atm.

  After the AlN crystal was grown for 30 hours under the above-described conditions, the SiC substrate with the AlN film grown on the surface was taken out from the reaction tube 12. Since the thickness of the AlN film was 2100 μm, the growth rate of the AlN crystal could be estimated to be 70 μm / hr.

(Example 8)
A GaN film was grown on the sapphire substrate using the vapor phase growth apparatus 10B shown in FIG. As the vapor phase growth apparatus 10B, the cross-sectional area of the supply port 28 is about 962mm ^2, the total cross-sectional area of the small holes 31a is used as approximately 30 mm ^2. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 100 mm. After the GaAs substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1050 ° C. Ga melt was used as the Ga raw material. In a state where the Ga melt placed on the quartz boat was heated to 800 ° C., HCl gas diluted with H ₂ gas was flowed to generate GaCl gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average partial pressure of GaCl in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.01 atm.

  After allowing the GaN crystal to grow for 30 hours under the above-described conditions, the GaAs substrate having a GaN film grown on the surface was taken out from the reaction tube 12. Since the film thickness of the GaN film was 4000 μm, the growth rate of the GaN crystal could be estimated as 133 μm / hr.

(Comparative Example 1)
An AlN film was grown on the SiC substrate using the vapor phase growth apparatus 10A shown in FIG. As the vapor phase growth apparatus 10A, an apparatus having x of 10 mm, L of 100 mm, d of 10 mm, y of 2 mm, l of 50 mm, and m of 150 mm was used (see FIG. 2). In the vapor phase growth apparatus 10A, the size corresponding to z in FIG. 2 is equal to x, and is 10 mm in this comparative example. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 50 mm. After the SiC substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1100 ° C. Al pellets were used as the Al raw material. While the Al pellets placed on the quartz boat were heated to 500 ° C., HCl gas diluted with N ₂ gas was flowed to generate AlCl ₃ gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average AlCl ₃ partial pressure in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.03 atm.

  After the AlN crystal was grown for 30 hours under the above-described conditions, the SiC substrate with the AlN film grown on the surface was taken out from the reaction tube 12. Since the thickness of the AlN film was 1110 μm, the growth rate of the AlN crystal could be estimated to be 37 μm / hr.

(Comparative Example 2)
A GaN film was grown on the sapphire substrate using the vapor phase growth apparatus 10A shown in FIG. As the vapor phase growth apparatus 10A, an apparatus having x of 10 mm, L of 100 mm, d of 10 mm, y of 2 mm, l of 150 mm, and m of 150 mm was used (see FIG. 2). In the vapor phase growth apparatus 10A, the size corresponding to z in FIG. 2 is equal to x, and is 10 mm in this comparative example. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the substrate surface was about 50 mm. After the sapphire substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1050 ° C. Ga melt was used as the Ga raw material. In a state where the Ga melt placed on the quartz boat was heated to 800 ° C., HCl gas diluted with H ₂ gas was flowed to generate GaCl gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average partial pressure of GaCl in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.01 atm.

  After the GaN crystal was grown for 30 hours under the above conditions, the substrate on which the GaN film was grown was taken out from the reaction tube 12. Since the film thickness of the GaN film was 2460 μm, the growth rate of the GaN crystal could be estimated as 82 μm / hr.

(Comparative Example 3)
An AlN film was grown on the SiC substrate using the vapor phase growth apparatus 10C shown in FIG. As the vapor phase growth apparatus 10C, the one having a supply port 28 having a cross-sectional area of about 962 mm ² and a supply port 30 having a cross-sectional area of about 294 mm ² was used. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 100 mm. After the SiC substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1100 ° C. Al pellets were used as the Al raw material. While the Al pellets placed on the quartz boat 20 were heated to 500 ° C., HCl gas diluted with N ₂ gas was flowed to generate AlCl ₃ gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average AlCl ₃ partial pressure in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.03 atm.

  After the AlN crystal was grown for 30 hours under the above-described conditions, the SiC substrate with the AlN film grown on the surface was taken out from the reaction tube 12. Since the thickness of the AlN film was 1240 μm, the growth rate of the AlN crystal could be estimated to be 41 μm / hr.

(Comparative Example 4)
A GaN film was grown on the sapphire substrate using the vapor phase growth apparatus 10C shown in FIG. As the vapor phase growth apparatus 10C, the one having a supply port 28 having a cross-sectional area of about 962 mm ² and a supply port 30 having a cross-sectional area of about 294 mm ² was used. The distance d1 between the supply port 28 in the tube axis direction of the reaction tube 12 and the center point of the SiC substrate surface was set to about 100 mm. After the GaAs substrate was placed on the substrate holder 14, the temperature of the substrate holder 14 was raised to 1050 ° C. Ga melt was used as the Ga raw material. In a state where the Ga melt placed on the quartz boat was heated to 800 ° C., HCl gas diluted with H ₂ gas was flowed to generate GaCl gas. On the other hand, NH ₃ gas was used as a nitrogen raw material. The gas flow rate was adjusted so that the average partial pressure of GaCl in the reaction tube 12 was 0.01 atm and the NH ₃ partial pressure was 0.2 atm. The HCl partial pressure was 0.01 atm.

  After allowing the GaN crystal to grow for 30 hours under the above-described conditions, the GaAs substrate having a GaN film grown on the surface was taken out from the reaction tube 12. Since the film thickness of the GaN film was 2520 μm, the growth rate of the GaN crystal could be estimated as 84 μm / hr.

It is a figure which shows typically the vapor phase growth apparatus which concerns on 1st Embodiment. It is a figure which shows typically the principal part of the vapor phase growth apparatus shown by FIG. It is a figure which shows typically the vapor phase growth apparatus in the development stage of the vapor phase growth apparatus shown in FIG. It is a figure which shows typically the vapor phase growth apparatus which concerns on 2nd Embodiment. It is a figure which shows typically the vapor phase growth apparatus in the development stage of the vapor phase growth apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,10A, 10B, 10C ... Vapor phase growth apparatus, 12 ... Reaction tube, 24, 24A ... Supply tube, 28 ... 1st supply port, 30 ... 2nd supply port, 31 ... Head part, 31a ... Small hole 32 ... Gas flow adjusting part, 32a ... First part, 32b ... Second part, G1 ... First source gas, G2 ... Second source gas, M ... Compound semiconductor film (compound semiconductor), W ... substrate.

Claims (4)

A reaction tube for growing a compound semiconductor by mixing the first source gas and the second source gas;
A first supply pipe inserted into the reaction tube for supplying the first source gas into the reaction tube;
A second supply pipe connected to the reaction pipe for supplying the second source gas into the reaction pipe;
A substrate holder for holding a substrate near a first supply port formed at an end portion of the first supply tube located in the reaction tube;
The first supply pipe and the reaction tube form a double tube structure by having the outer wall of the first supply pipe facing the inner wall of the reaction tube,
The second supply pipe is connected to the reaction tube so that a space formed between the outer wall of the first supply pipe and the inner wall of the reaction tube becomes a flow path for the second source gas. And
The end of the first supply pipe located in the reaction tube has a gas flow adjustment swelled toward the inner wall of the reaction tube so as to reduce the cross-sectional area of the flow path of the second source gas. Part is provided,
The vapor phase growth apparatus, wherein an opening area of the first supply port of the first supply pipe is smaller than a cross-sectional area of the first supply pipe. A reaction tube for growing a compound semiconductor by mixing the first source gas and the second source gas;
A first supply pipe inserted into the reaction tube for supplying the first source gas into the reaction tube;
A second supply pipe connected to the reaction pipe for supplying the second source gas into the reaction pipe;
A substrate holder for holding a substrate near a first supply port formed at an end portion of the first supply tube located in the reaction tube;
The first supply pipe and the reaction tube form a double tube structure by having the outer wall of the first supply pipe facing the inner wall of the reaction tube,
The second supply pipe is connected to the reaction tube so that a space formed between the outer wall of the first supply pipe and the inner wall of the reaction tube becomes a flow path for the second source gas. And
The end of the first supply pipe located in the reaction tube has a gas flow adjustment swelled toward the inner wall of the reaction tube so as to reduce the cross-sectional area of the flow path of the second source gas. Part is provided,
The vapor phase growth apparatus, wherein the first supply port is closed by a head portion provided with a plurality of small holes.   A compound semiconductor film grown using the vapor phase growth apparatus according to claim 1.   A method for growing a compound semiconductor film, comprising growing a compound semiconductor film using the vapor phase growth apparatus according to claim 1.

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