JP7002730B2 - Vapor deposition equipment - Google Patents

Description

This specification discloses a technique relating to a vapor phase growth apparatus for a compound semiconductor.

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

JP-A-2002-316892

If GaN long crystals can be grown, a plurality of wafers can be produced from one long crystal, so that the substrate manufacturing cost can be reduced. However, it is difficult to grow a long crystal of GaN. One of the factors is that cracks occur when long crystals are grown. This is because the end face of the outer peripheral portion of the grown crystal is not perpendicular to the surface of the seed substrate and becomes a tapered surface. When the tapered surface takes in oxygen, the lattice constant becomes small and stress is generated, so that the grown crystal cracks.

This specification discloses a vapor deposition apparatus. This vapor deposition apparatus comprises a reaction vessel. The vapor phase growth apparatus is arranged in a reaction vessel and includes a substrate holder having a substrate holding surface for holding the substrate on the first surface. The vapor deposition apparatus includes a ring portion having a hole corresponding to the substrate held on the substrate holding surface. The vapor phase growth apparatus includes a raw material gas supply pipe that supplies a first raw material gas and a second raw material gas that reacts with the first raw material gas into the reaction vessel. The first raw material gas and the second raw material gas are raw material gases for growing crystals of compound semiconductors on the surface of the substrate. The vapor phase growth apparatus includes an actuator that moves at least one of the substrate holder and the ring portion along an axis perpendicular to the substrate holding surface. The actuator keeps the distance between the surface of the crystal of the compound semiconductor growing on the substrate and the surface of the ring portion constant.

In the vapor phase growth apparatus of the present specification, the actuator can maintain a constant distance between the surface of the crystal of the compound semiconductor growing on the substrate and the surface of the ring portion. As a result, even when the crystal grows and becomes thicker, the flow of the first and second raw material gases on the outer peripheral portion of the substrate can be kept constant. As a result, a homogeneous crystal can be obtained even if the crystal becomes thick. Further, by supporting the outer peripheral portion of the crystal with the inner wall surface of the ring portion, the end surface of the outer peripheral portion of the grown crystal can be made a plane perpendicular to the surface of the substrate. It is possible to prevent a situation in which cracks are generated in the grown crystal.

The actuator may move the substrate holder to the second surface side opposite to the first surface. The moving speed of the substrate holder may be equal to the growth speed of the compound semiconductor crystal in the thickness direction.

The actuator may maintain a state in which the distance from the substrate holding surface to the surface of the ring portion is larger than the distance from the substrate holding surface to the surface of the crystal of the compound semiconductor growing on the substrate by a predetermined distance.

The surface of the ring portion may be covered with a predetermined metal capable of decomposing the second raw material gas by a catalytic effect.

The predetermined metal may be a metal containing tungsten.

The gas supply port of the raw material gas supply pipe may be arranged at a position facing the substrate holding surface. The actuator may move the substrate holder so as to maintain a constant distance between the surface of the compound semiconductor crystal growing on the substrate and the gas supply port.

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

It is schematic cross-sectional view of the vapor phase growth apparatus which concerns on Example 1 as seen from the side. It is a partially enlarged view of the sectional view of the substrate holder, the ring plate and the shower head. It is the figure which looked at the sectional view in line III-III from the vertical lower side. It is the figure which looked at the sectional view in line IV-IV from the vertical upper side. It is a partially enlarged view of the sectional view of the substrate holder, the ring plate and the shower head. It is a partially enlarged view of the sectional view of the substrate holder, the ring plate and the shower head. It is a partially enlarged view of the sectional view of the substrate holder, the ring plate and the shower head in the comparative example. It is a partially enlarged view of the sectional view of the substrate holder, the ring plate and the shower head in the comparative example. It is schematic cross-sectional view of the vapor phase growth apparatus which concerns on Example 2 as seen from the side. It is the schematic sectional drawing which looked at the side view of the vapor phase growth apparatus which concerns on Example 3. FIG.

<Structure of vapor phase growth device>
FIG. 1 shows a schematic cross-sectional view of the vapor phase growth apparatus 1 according to the technique of the present specification as viewed from the side surface. The vapor phase growth apparatus 1 is an example of an apparatus configuration for carrying out the 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 raw material gas supply unit 20 and a substrate holder 11 are arranged.

FIG. 2 shows a partially enlarged view of a cross-sectional view of the substrate holder 11, the ring plate 12, and the shower head 50. The board holder 11 includes a holder body 11b and a support portion 11c. A substrate holding surface 11a is provided on the lower surface of the substrate holder 11. The support portion 11c of the substrate holder 11 holds the substrate 13 so that the surface of the substrate 13 faces substantially vertically downward. Note that "substantially vertically downward" is not limited to the mode in which the normal of the substrate coincides with the vertically downward direction. The concept is that the normal of the substrate includes an inclination of up to 45 degrees with respect to the vertical downward direction. The substrate 13 is a seed substrate for growing a GaN single crystal, and is a GaN single crystal. The surface of the substrate 13 is a + c plane (also referred to as a (0001) plane).

The surface of the support portion 11c is covered with the predetermined metal 17. The predetermined metal 17 is a metal capable of decomposing the second raw material gas G2 by a catalytic effect. In this embodiment, a material containing tungsten is used as the predetermined metal 17. This has the effect of suppressing the precipitation of GaN polycrystals on the surface of the support portion 11c. This is because the active hydrogen generated by decomposing NH ₃ due to the catalytic effect suppresses the precipitation of GaN polycrystals.

A ring plate 12 is arranged under the board holder 11. The surface of the ring plate 12 is covered with the predetermined metal 18. The predetermined metal 18 is a metal capable of decomposing the second raw material gas G2 by a catalytic effect. In this embodiment, a material containing tungsten is used as the predetermined metal 18. This has the effect of suppressing the precipitation of GaN polycrystals on the surface of the ring plate 12.

The lower surface 12a of the ring plate 12 is a surface corresponding to the substrate holding surface 11a. In this embodiment, the lower surface 12a is a plane parallel to the substrate holding surface 11a. The ring plate 12 includes a hole portion 12b corresponding to the substrate 13 held on the substrate holding surface 11a. Here, the central axis of the substrate holder 11 is A1. The position of the inner wall 11cw of the support portion 11c is defined as the position P1. The position of the inner wall 12w forming the hole portion 12b of the ring plate 12 is defined as the position P2. The distance D2 from the central axis A1 to the position P2 may be equal to or greater than the distance D1 from the central axis A1 to the position P1.

FIG. 3 shows a cross-sectional view taken along the line III-III of FIG. 1 as viewed from vertically below. As shown in FIG. 3, the ring plate 12 is a ring-shaped member. As described above, when the distance D2 is the distance D1 or more, the entire surface of the exposed surface of the substrate 13 is included in the range of the hole portion 12b of the ring plate 12.

The lower end of the rotating shaft 14 is connected to the upper part of the board holder 11. The upper end of the rotating shaft 14 projects to the outside of the reaction vessel 10 (see FIG. 1). The upper end of the rotating shaft 14 is connected to the actuator 15. As a result, the substrate holder 11 is directed upward (direction toward the upper surface 11d of the substrate holder 11) and downward (direction toward the substrate holding surface 11a of the substrate holder 11) along the central axis A1 perpendicular to the substrate holding surface 11a. ) Can be moved. Further, the substrate holder 11 can be rotated by the actuator 15.

The structure of the raw material gas supply unit 20 will be described. The raw material gas supply unit 20 is a cylindrical member. The raw material gas supply unit 20 includes a cylindrical cover 24. A disk-shaped shower head 50 is arranged at the upper end of the cover 24. An inlet of the HCl gas supply pipe 25 and an inlet of the second raw material gas supply pipe 22 are arranged in the lower part of the raw material gas supply unit 20. A first valve 61 is arranged 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 raw material gas generation unit 41. The first raw material gas generation unit 41 stores metallic gallium inside. The first raw material gas generation unit 41 is a portion that generates the first raw material gas G1 containing GaCl. The first raw material gas supply pipe 21 is a pipe for supplying the first raw material gas G1. The inlet of the first raw material gas supply pipe 21 is connected to the first raw material gas generation unit 41. The outlet of the first raw material gas supply pipe 21 is connected to the shower head 50. A second valve 62 is arranged at the inlet of the second raw material gas supply pipe 22. The second valve 62 controls the supply of the gas including the second raw material gas G2. The second raw material gas G2 is a gas containing NH ₃ . The outlet of the second raw material gas supply pipe 22 is connected to the shower head 50.

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

The shower head 50 is a portion for discharging the first raw material gas G1 and the second raw material gas G2 to the vicinity of the surface of the substrate 13. The shower head 50 is arranged at a position facing the substrate holding surface 11a of the substrate holder 11. The first raw material gas G1 and the second raw material gas G2 discharged from the shower head 50 flow vertically upward in the reaction vessel 10 in the direction of arrow Y1.

The structure of the shower head 50 will be described with reference to FIG. FIG. 4 is a view of the cross-sectional view taken along the line IV-IV of FIG. 1 as viewed from above vertically. On the surface of the shower head 50, a plurality of first gas supply ports 51 for discharging the first raw material gas G1 and a plurality of second gas supply ports 52 for discharging the second raw material gas G2 are arranged. By discharging the first raw material gas G1 and the second raw material gas G2 from a large number of gas supply ports, the amount of gas supplied to the surface of the substrate 13 can be made uniform in the plane. Therefore, it is possible to suppress in-plane variation in the grown GaN crystal thickness. On the surface of the shower head 50, a region where the first gas supply port 51 and the second gas supply port 52 are not formed is covered with a predetermined metal 53. In this embodiment, a material containing tungsten is used as the predetermined metal.

A gas exhaust pipe 23 for exhausting the gas in the reaction vessel 10 is configured around the raw material gas supply unit 20. This will be described with reference to FIG. A cylindrical raw material 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 raw material gas supply unit 20. This annular gap functions as a gas exhaust pipe 23.

Further, the inlet 23a (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 the arrow Y2 in FIG. 1, the first raw material gas G1 and the second raw material gas G2 used for GaN crystal growth on the surface of the substrate 13 are exhausted toward the side surface of the shower head 50 and downward of the substrate 13. Can be made to. An outlet 23b of the gas exhaust pipe 23 is arranged at the lower end of the reaction vessel 10. The gas sucked from the inlet 23a of the gas exhaust pipe 23 is discharged to the vent line from the outlet 23b.

A specific gas supply pipe 16 is provided in the upper part of the reaction vessel 10. The specific gas G3 is supplied to the inlet of the specific gas supply pipe 16. As shown by the arrow Y3 in FIG. 1, the specific gas G3 flows vertically downward from above the substrate holder 11 and is sucked into the inlet 23a of the gas exhaust pipe 23. Thereby, the 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 raw material gas G1 and the second raw material 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 arranged on the outside of the reaction vessel 10. A partition wall 42 is arranged near the boundary between the region H1 in which the upper heater 31 is arranged and the region H2 in which the lower heater 32 is arranged. The upper heater 31 can heat the substrate 13 to a temperature sufficient for GaN crystal growth (1050 ± 50 ° C.). Further, the lower heater 32 can heat the first raw material gas generation unit 41 to a temperature (750 ° C.) or higher required for stable generation of GaCl.

<Chemical vapor deposition method>
An example of the air layer growth condition by the HVPE method is listed. The molar ratio of GaCl in the first raw material gas G1 and _NH3 in the second raw material gas G2 was 1:20. The pressure in the reaction vessel 10 was 1000 hPa.

The upper heater 31 and the lower heater 32 are turned on, and the supply of the first raw material gas G1 and the second raw material gas G2 is started. As a result, vapor deposition of the GaN crystal layer can be performed on the substrate 13. The growth rate of the GaN crystal layer is about 50 to 1000 μm / hour. When the GaN crystal layer 19 grows from the state of FIG. 2 to the state of FIG. 5, the actuator 15 starts control to move the substrate holder 11 upward (in the direction of arrow Y10) along the central axis A1. The ascending rate of the substrate holder 11 is equivalent to the growth rate of the GaN crystal layer 19. The growth rate may be predicted by calculation or may be calculated by actual measurement. In the state of FIG. 5, the distance D3 from the substrate holding surface 11a to the lower surface 12a of the ring plate 12 is larger than the distance D4 from the substrate holding surface 11a to the surface 19a of the GaN crystal layer 19 by a predetermined distance PD. be. In other words, the state of FIG. 5 is a state in which the lower surface 12a of the ring plate 12 projects toward the shower head 50 by a predetermined distance PD with respect to the surface 19a of the GaN crystal layer 19. The predetermined distance PD can be determined to an arbitrary value by an experiment or the like.

FIG. 6 shows a state in which the GaN crystal layer 19 is further grown by the thickness T1 from the state of FIG. Since the ascending speed of the substrate holder 11 is the same as the growth rate of the GaN crystal layer 19, the substrate holder 11 also increases by the same distance as the thickness T1. As a result, the state in which the distance D3 is larger than the distance D4 by a predetermined distance PD is maintained. Further, the distance D5 between the surface 19a of the GaN crystal layer 19 and the surface of the shower head 50 (gas supply port) is maintained constant in FIGS. 5 and 6.

<Effect>
First, a comparative example will be described with reference to FIGS. 7 and 8. The comparative example is an example in the case where the ring plate 12 according to this embodiment is not provided. When the GaN crystal layer 19 grows and becomes thicker from the state of FIG. 7 to the state of FIG. 8, the substrate holder 11 is moved upward along the central axis A1 (in the direction of arrow Y10) according to the increase in thickness. ) Will be described. In this case, the distance D5 between the surface 19a of the GaN crystal layer 19 and the surface of the shower head 50 (gas supply port) is maintained constant. However, the distance D6 between the lower surface 11cs of the support portion 11c arranged on the outer periphery of the GaN crystal layer 19 and the surface of the shower head 50 is not constant and increases as the substrate holder 11 rises. Then, the flow of the first and second raw material gases on the outer peripheral portion of the substrate cannot be kept constant. That is, the gas flow Y20a shown in FIG. 7 and the gas flow Y20b shown in FIG. 8 are different. Then, the flow path of the gas flow becomes unstable, and the supply of raw materials to the surface 19a of the GaN crystal layer 19 and the temperature distribution change from the initial stage of growth, so that the crystal quality and distribution may deteriorate. Further, the end surface 19b of the outer peripheral portion of the GaN crystal layer 19 that has grown into a thick film with the crystal end surface open is not perpendicular to the surface (c surface) of the substrate 13, and becomes a tapered surface (FIG. 8). This is because the tapered surface is more stable than the vertical surface. Such a tapered surface is a surface that is more stable than the m surface ({10-11} surface) and a surface that is more stable than the a surface ({11-21} surface, {11-22} surface). When these tapered surfaces take in oxygen, the lattice constant becomes small and stress is generated, so that the grown GaN crystal layer 19 is cracked.

On the other hand, the vapor phase growth apparatus 1 of this embodiment includes a ring plate 12 as shown in FIGS. 5 and 6. The position of the ring plate 12 is fixed with respect to the shower head 50. Therefore, even when the substrate holder 11 is moved upward according to the increase in the thickness of the GaN crystal layer 19, the distance D7 between the lower surface 12a of the ring plate 12 and the surface of the shower head 50 can be kept constant. As a result, as the first effect of the ring plate 12, the present inventors can obtain crystals that are uniform in the thickness direction even when the GaN crystal layer 19 is grown for a long time (that is, thick film growth). I found it. It is considered that this is because the ring plate 12 can maintain a constant flow of the first and second raw material gases in the outer peripheral portion of the substrate even when the substrate holder 11 is raised. That is, it is considered that the gas flow Y20 shown in FIGS. 5 and 6 can be made the same even during the growth of the GaN crystal layer 19.

Further, as a second effect of the ring plate 12, the present inventors have found that the end face 19b of the outer peripheral portion of the GaN crystal layer 19 can be made perpendicular to the surface of the substrate 13. It is considered that this is because the lower surface 12a of the ring plate 12 can be formed so as to protrude toward the shower head 50 by a predetermined distance PD with respect to the surface 19a of the GaN crystal layer 19 (FIGS. 5 and 6). reference). This will be described in detail. By projecting the lower surface 12a of the ring plate 12, gas flow retention can be formed in the region R1 near the boundary between the ring plate 12 and the GaN crystal layer 19. It is assumed that a part of this stagnant gas contributes to the formation of vertical crystal planes (for example, m plane ({1-100} plane) and a plane ({11-20} plane)) along the wall surface. Conceivable. As a result, it is possible to prevent a situation in which oxygen atoms are incorporated into the grown GaN crystal layer end face 19b and cracks are formed in the GaN crystal layer 19. Further, when cutting out a plurality of wafers from the GaN crystal layer 19, it is possible to cut out a wafer having a certain area.

FIG. 9 shows a schematic cross-sectional view of the vapor phase growth apparatus 201 according to the second embodiment as viewed from the side surface. The vapor phase growth apparatus 201 according to the second embodiment changes the supply directions of the first raw material gas G1 and the second raw material gas G2 from upward to sideways with respect to the vapor phase growth apparatus 1 according to the first embodiment, and is a substrate. It has a configuration in which the surface orientation is changed from downward to upward. Since the basic configuration of the vapor phase growth apparatus 201 of the second embodiment is the same as that of the vapor phase growth apparatus 1 of the first embodiment, detailed description thereof will be omitted.

The gas phase growth device 201 includes a reaction vessel 210, a substrate holder 211, a ring plate 212, a first raw material gas supply pipe 221 and a second raw material gas supply pipe 222, and a gas exhaust pipe 271. The board holder 211 includes a holder body 211b and a support portion 211c. A substrate holding surface 211a is provided on the upper surface of the substrate holder 211. The substrate 213 is held on the substrate holding surface 211a.

A ring plate 212 is arranged on the upper side of the board holder 211. The upper surface 212a of the ring plate 212 is a surface corresponding to the substrate holding surface 211a. In this embodiment, the upper surface 212a is a plane parallel to the substrate holding surface 211a. The ring plate 212 includes a hole 212b corresponding to the substrate 213.

An actuator 215 is connected to the lower part of the board holder 211 via a rotating shaft 214. The substrate holder 211 can be moved in the vertical direction (z direction in FIG. 9) along the central axis A2 perpendicular to the substrate holding surface 211a.

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

A heater 231 is arranged on the outer periphery of the reaction vessel 210 so as to surround the substrate holder 211. The heater 231 is a device that heats the substrate 213 by a hot wall method. As a result, the substrate 213 can be maintained at a temperature sufficient for GaN crystal growth (1050 ± 50 ° C.). Further, it is possible to suppress the precipitation of by-products on the inner wall of the reaction vessel 210. A heater 233 is arranged on the outside of the second raw material gas supply pipe 222 so as to surround the first raw material gas generation unit 241. As a result, the first raw material gas generation unit 241 can be maintained at 750 ° C. or higher in order to generate GaCl.

<Effect>
The vapor phase growth apparatus 201 of the second embodiment includes a ring plate 212. The ring plate 212 is fixed in the reaction vessel 210. Therefore, by setting the descending speed of the substrate holder 211 and the growth rate of the GaN crystal layer growing on the substrate 213 to be equal, the distance between the upper surface 212a of the ring plate 212 and the surface of the GaN crystal layer is made constant. be able to. As a result, even when the substrate holder 211 is lowered, it is possible to maintain a constant flow of the first and second raw material gases on the outer peripheral portion of the substrate. A GaN crystal layer 19 that is homogeneous in the thickness direction can be grown. Further, it is possible to generate the retention of the gas flow in the region of the outer peripheral portion of the surface of the GaN crystal layer. This makes it possible to make the end face of the outer peripheral portion of the grown GaN crystal layer perpendicular to the surface of the substrate 213. Therefore, it is possible to prevent a situation in which the grown GaN crystal layer is cracked.

FIG. 10 shows a schematic cross-sectional view of the vapor phase growth apparatus 301 according to the third embodiment as viewed from the side surface. The vapor phase growth apparatus 301 according to the third embodiment positions the first raw material gas supply pipe 221 and the second raw material gas supply pipe 222 with respect to the vapor phase growth apparatus 201 according to the second embodiment from the right side of the substrate to the upper side of the substrate. It has a configuration that has been moved to the side. Further, it has a configuration in which the position of the gas exhaust pipe 271 is moved from the left side of the substrate to the lower side of the substrate. Since the same components as those of the vapor phase growth apparatus 201 of the second embodiment are designated by the same reference numerals, detailed description thereof will be omitted.

Also in the gas phase growth apparatus 301 of the third embodiment, by setting the descending speed of the substrate holder 211 and the growth rate of the GaN crystal layer growing on the substrate 213 to be equal, the upper surface 212a of the ring plate 212 and the GaN crystal The distance from the surface of the layer can be constant. Since the flow of the first and second raw material gases can be kept constant in the outer peripheral portion of the substrate, a GaN crystal layer homogeneous in the thickness direction can be grown. Further, since the gas flow can be retained in the region of the outer peripheral portion of the surface of the GaN crystal layer, the end face of the outer peripheral portion of the grown GaN crystal layer can be made perpendicular to the surface of the substrate 213. Become.

<Modification example>
Although the examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

The lower surface 12a of the ring plate 12 described with reference to FIG. 2 is not limited to a flat surface. It may be a curved surface or a part of it may be a flat surface. When the lower surface 12a includes a flat surface portion, the flat surface portion may have an inclination with respect to the substrate holding surface 11a. The same applies to the upper surface 212a of the ring plate 212 of FIGS. 9 and 10.

The shape of the substrate 13 is not limited to a circle. Substrates with shapes such as squares and hexagons can also be used.

The ring plates 12 and 212 are not limited to a circular shape, but may have a polygonal shape, a rectangular shape, or the like. Further, the ring plates 12 and 212 may have a substantially ring shape, and do not have to have a completely closed shape. For example, it may have a C-shaped shape.

In FIG. 2, the case where the distance D2 is equal to or greater than the distance D1 has been described, but the present invention is not limited to this form. For example, the distance D2 may be smaller than the distance D1. As a result, even when the crystal diameter is reduced in the initial period until the surface of the GaN crystal layer 19 reaches the upper surface of the ring plate 12 (that is, the period until the ring plate 12 starts to function), the crystal diameter after reduction is reduced. It becomes possible to correspond to the inner diameter of the hole portion 12b of the ring plate 12.

The case where the surface of the seed substrate is the + c surface has been described, but the present invention is not limited to this form. Various surfaces can be used as the surface of the seed substrate.

As an example of forming the end face perpendicular to the crystal surface, the case of the m-plane ({1-100} plane) and the a-plane ({11-20} plane) has been described, but the present invention is not limited to this form. Various crystal planes and intermediate surface morphologies can be used.

Tungsten has been described as an example of a metal in which NH ₃ can be decomposed by a catalytic effect, but the material is not limited to this material. Tungsten oxide (WOx), tungsten carbide (WCx), tungsten nitride (WNx), and the like can also be used. Further, metals containing tungsten (tungsten alloy) and their oxides, carbides and nitrides can also be used. Other metals such as ruthenium, iridium, platinum, molybdenum, palladium, rhodium, iron, nickel and rhenium can also be used. Further, oxides, carbides and nitrides of these metals, alloys containing these metals and the like can also be used.

The temperature sufficient for GaN crystal growth was described as 1050 ± 50 ° C. Further, it was explained that the temperature required for the generation of GaCl was 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.

The number and arrangement of the first raw material gas supply pipe and the second raw material gas supply pipe described in the present specification are examples, and are not limited to this form.

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

The technique described in the present specification can be applied 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 raw material gas G2.

The first raw material gas G1 and the _second raw material gas G2 may be flown together with a carrier gas such as H2 or _N2 .

The technical elements described herein or in the drawings exhibit their 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 techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

The ring plate 12 is an example of a ring portion. The lower surface is an example of the first surface. The upper surface is an example of the second surface.

1: Gas phase growth device 10: Reaction vessel 11: Substrate holder 12, 212: Ring plate 15: Actuator 17, 18, 53: Predetermined metal 21, 221: First raw material gas supply pipe 22, 222: Second raw material gas supply Pipes 41, 241: 1st raw material gas generator 50: Shower head

Claims (9)

With the reaction vessel,
A substrate holder arranged in the reaction vessel and having a substrate holding surface for holding the substrate on the first surface, and a substrate holder.
A ring portion having a hole corresponding to the substrate held on the substrate holding surface, and a ring portion.
A raw material gas supply pipe that supplies a first raw material gas and a second raw material gas that reacts with the first raw material gas into the reaction vessel, and the first raw material gas and the second raw material gas are on the surface of the substrate. The raw material gas supply pipe, which is the raw material gas for growing the crystals of the compound semiconductor,
An actuator that moves at least one of the substrate holder and the ring portion along an axis perpendicular to the substrate holding surface, the surface of the crystal of the compound semiconductor growing on the substrate and the ring portion. The actuator that maintains a constant distance from the surface,
Equipped with
The surface of the ring portion is covered with a predetermined metal capable of decomposing the second raw material gas by a catalytic effect.
The second raw material gas is a gas phase growth apparatus for compound semiconductors, which is a gas that generates active hydrogen by being decomposed by the catalytic effect . The second raw material gas is NH ₃ The vapor phase growth apparatus according to claim 1, wherein the gas comprises. The actuator moves the substrate holder to the second surface side opposite to the first surface.
The vapor phase growth apparatus according to claim 1 or 2 , wherein the moving speed of the substrate holder is equivalent to the growth rate in the thickness direction of the crystal of the compound semiconductor. The actuator maintains a state in which the distance from the substrate holding surface to the surface of the ring portion is larger than the distance from the substrate holding surface to the surface of the crystal of the compound semiconductor growing on the substrate by a predetermined distance. The vapor phase growth apparatus according to any one of claims 1 to 3 . Any of claims 1 to 4, wherein the predetermined metal includes tungsten or a metal containing tungsten, an oxide of tungsten or a metal containing tungsten, a carbide of a metal containing tungsten or tungsten, or a nitride of a metal containing tungsten or tungsten. The gas phase growth apparatus according to item 1 . The gas supply port of the raw material gas supply pipe is arranged at a position facing the substrate holding surface.
The actuator moves the substrate holder so as to maintain a constant distance between the surface of the crystal of the compound semiconductor growing on the substrate and the gas supply port.
The vapor phase growth apparatus according to any one of claims 1 to 5. The first raw material gas is a gas containing GaCl, and is a gas containing GaCl.
The vapor phase growth apparatus according to any one of claims 1 to 6, wherein the second raw material gas is a gas containing NH ₃ . The process of arranging the substrate in the reaction vessel and
A raw material gas supply step of supplying a first raw material gas and a second raw material gas that reacts with the first raw material gas into the reaction vessel, wherein the first raw material gas and the second raw material gas are on the surface of the substrate. The raw material gas supply process, which is the raw material gas for growing the crystals of the compound semiconductor,
During the execution of the raw material gas supply step, a moving step of moving the ring portion having a hole corresponding to the substrate relative to the substrate along an axis perpendicular to the substrate.
Equipped with
The surface of the ring portion is covered with a predetermined metal capable of decomposing the second raw material gas by a catalytic effect.
The second raw material gas is a gas that generates active hydrogen by being decomposed by the catalytic effect.
The moving step is a method for growing a gas phase of a compound semiconductor, which is performed so as to maintain a constant distance between the surface of the crystal of the compound semiconductor growing on the substrate and the surface of the ring portion in the axial direction. The second raw material gas is NH ₃ The gas phase growth method according to claim 8, wherein the gas comprises.

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