JP2013038099A - Vapor growth device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device structure for larger batch size with uniformity being improved in mass production of chemical vapor deposition (CVD) for growing a crystal film on a substrate, in which sticking of CVD gas to a pump of an exhaust system or to an exhaust piping is reduced by extending a cleaning/replacement cycle of a component of the device for improved consumption efficiency of the CVD gas on the substrate, and further a flow path that crosses a heating space is preferred to be shortened since polymerization reaction occurs in a vapor phase to generate granular dust when organic metal gas is used as CVD gas.SOLUTION: A plurality of susceptors to be heated, on the surface of which a substrate is placed, are arranged radially. While the susceptors arranged radially are rotated, thermal decomposition CVD gas is supplied from an outer periphery so that a CVD film is grown on the substrate. At the center of arrangement of the susceptors arranged radially, an exhaust pipe that can be heated is disposed, for exhausting CVD gas through the exhaust pipe. Thus issues are solved in a vapor growth device for a crystal film.

Description

The present invention relates to an apparatus for growing a thin film on a substrate.

An apparatus for growing a film from a gas phase to a substrate at a high temperature has been developed with the development of the semiconductor industry. An apparatus for growing a crystal film has a special structure because it is necessary to clean the atmosphere and manage particle dust on the substrate with high reproducibility among vapor phase growth apparatuses. Several typical structures have been invented in accordance with the size of the substrate for the mass production apparatus that competes for cost.

In the silicon semiconductor industry, there was a time when the development of mounting bipolar transistors on LSIs (Large Scale Integrated Circuits) competed. The transistor has a crystal structure in which a silicon crystal film is grown on a silicon substrate. An apparatus for growing this crystal film was called a silicon epitaxial apparatus. Since silicon substrates (sometimes called wafers) are currently 12 inches in diameter, the current epitaxial equipment is single wafer.

This is because when the substrate is large, an apparatus structure for processing one substrate is suitable for obtaining uniformity. However, in the 1980's when processing 2 inch and 4 inch substrates, the batch method was used. At that time, several device structures were invented because of the need to process a large number of substrates.

Although the silicon semiconductor industry has matured, devices using compound semiconductors are now growing as an industry. The industry is a laser device using a GaAs (gallium arsenide) substrate and an LED (Light Emitting Diode) device using a GaN (gallium nitride) or sapphire substrate.

In these industries, substrates of 2 to 4 inches are still mainstream. This is an industry that can increase the production efficiency as the number of substrates that can be processed in one growth increases. In the silicon industry, it was possible to increase the size of the substrate, so the size of the substrate was increased to reduce the manufacturing cost. Therefore, there is a reality that the substrate is now up to 12 inches. However, although the history of the industry is as long as that of silicon semiconductors, compound semiconductors still use a 4-inch substrate, but there is still a practical limit.

One reason is that there is a problem of warping of the substrate and accompanying cracks in the grown crystal film. This problem becomes conspicuous as the substrate becomes larger. Therefore, in the compound semiconductor industry, the era of still using 2 inch or 4 inch substrates continues. The era when the market was small lasted for a long time, but now it is growing rapidly. As a result, cost competition began to intensify in the market. Since there is a problem of warping, the method of enlarging the substrate in the same way as a silicon semiconductor is not used to reduce the cost. Therefore, increasing the number of substrates that can be grown in one process is now competitive.

An organic metal gas is used for the growth of the compound semiconductor film. This gas is thermally decomposed to form a polymer in the gas phase. Because of this property, there are few types of structures of crystal growth apparatuses. The basic structure is to use one susceptor (a heating plate on which a substrate is placed) and to place one or more substrates thereon, and it has not evolved. The only way to increase the batch size is to increase the susceptor in this basic structure.

On the other hand, there were many structural ideas for silicon epitaxial devices in the era of rapid industrial growth. Among them is the idea of using a large number of susceptors. As an example, the structure disclosed in Japanese Patent Laid-Open No. 60-090894 (Patent Document 1) is transferred and shown in FIG.

In this structure, a plurality of susceptors 11 are arranged radially, and a base body (same as a substrate) 4 is mounted on both surfaces of each susceptor 11. FIG. 2 shows the structure of the cylinder reaction chamber 12. The susceptor is heated by the heater 16 and rotated by the substrate rotation introducing device 15. 13 Chemical vapor deposition (CVD) gas is introduced from a plurality of inlets from the raw material blowing nozzle 13, flows from above the susceptor, thermally decomposes on the substrate on the susceptor, and grows a crystal film. Then, the air is exhausted from the exhaust port 14.

As another invention using a plurality of susceptors, a main diagram of Japanese Patent Laid-Open No. 03-142823 (Patent Document 2) is reprinted and schematically shown in FIG. The susceptor 302 is stacked by connecting bars 309 in multiple stages. One substrate 301 is placed on the susceptor 302. A work coil 305 is provided outside the quartz outer cylinder 304, and the susceptor 302 is inductively heated by passing an induced current through the coil. The susceptor rotates on the rotation shaft 303. CVD gas is introduced from gas supply pipes 306 a, 306 b, 306 c, and 306 d independently provided with blowout ports, thermally decomposed on the susceptor, a crystal film is grown on the substrate 301, and the gas exhaust pipe 307 The air is exhausted from the hole 308.

Two examples of the structure of the crystal film growth apparatus for increasing the batch size (increasing the number of substrates to be grown at one time) have been shown above.

As the batch size is increased, it is necessary to grow a heterocrystal whose crystal film is different from the substrate. In the case of heterocrystal growth, the atmosphere is reduced pressure and the linear velocity of the gas used is high. Prior Patent Document 3 published in 1987 an invention for growing a silicon carbide crystal film on a silicon substrate under reduced pressure. The present invention is a technique for growing a crystal film having a smooth surface on a heterogeneous substrate by slightly tilting the axis of the substrate. In recent years, silicon carbide has been put into practical use as a high breakdown voltage, high frequency, high power device crystal. GaN is also being put into practical use as a crystal for LED lighting and high-speed high-power devices. There is a growing market need for attempts to grow these crystals heterocrystals on a silicon crystal substrate in a large batch size.

JP-A-60-090894 Japanese Patent Laid-Open No. 03-142823 JP 62-155512 A

The above example showed that the batch size can be increased by using a structure that increases the susceptor. When considering mass production, structural improvement to increase batch size while improving uniformity is a fundamental issue. Although it is necessary to clean and replace the parts of the equipment, we want to lengthen this cycle. The first problem is to reduce the frequency of replacement of the quartz tube that maintains vacuum and airtightness. It is also desirable to increase the consumption efficiency of CVD gas on the substrate and reduce the adhesion of the exhaust system to pumps and exhaust pipes. In other words, we want to reduce the amount of unreacted CVD gas that is unused and thrown away. This is the second problem. When an organometallic gas is used as a CVD gas, a polymerization reaction occurs in the gas phase and particle dust is generated. Therefore, it is desired to shorten the flow path across the heating space. This is the third problem.

In order to solve these problems, an improved device structure is provided.

According to the present invention, as described in claim 1, a plurality of heated susceptors for placing a substrate on the surface are arranged in a radial manner, and the pyrolytic CVD gas is supplied from the outer periphery while rotating the susceptors in the radial arrangement. A CVD film is grown on the substrate, and a heatable exhaust pipe is arranged at the center of the radial arrangement susceptor, and the film is grown on the substrate by exhausting the CVD gas from the exhaust pipe. This is a manufacturing device.

The invention according to claim 2 is the manufacturing apparatus according to claim 1, wherein the susceptor is sandwiched between two or more heating disks.

The invention according to claim 3 is the manufacturing apparatus according to claims 1 and 2, wherein the heating disk is heated by induction heating.

According to a fourth aspect of the present invention, the film is a semiconductor film containing silicon, germanium, carbon, gallium, aluminum, indium, nitrogen, oxygen, magnesium, phosphorus, arsenic, or a laminated film thereof. It is a manufacturing apparatus of Claims 1-3 characterized by the above-mentioned.

The invention according to claim 5 is the manufacturing apparatus according to claims 1 to 4, wherein the susceptor is made of graphite.

The invention according to claim 6 is the manufacturing apparatus according to claims 1 to 5, wherein the substrate is mounted on both surfaces of the susceptor.

According to the first to third aspects of the present invention, the gas is introduced from the periphery where the plurality of susceptors on which the substrate is mounted is arranged and exhausted from the center, so that the thermally decomposed CVD gas keeps the reaction chamber chamber airtight. Flow away from the tube and do not touch. As a result, there are few films growing on the quartz tube, and the replacement frequency of the quartz tube is reduced. This solves the first problem.

The heated gas is thermally decomposed to grow a crystal film on the substrate. The travel distance of the gas may be longer than the diameter of the substrate. The third problem of short gas travel distance has been solved.

The distance between the radially arranged susceptors becomes narrower on the inside. When narrowed, the gas flow toward the center of the susceptor is faster toward the downstream. The fast flow thins the stagnant layer between the substrate and the gas, so that the diffusion of the reactive species is accelerated and the growth rate is increased. The radial arrangement improves uniformity because the growth rate increase effect of this thin stagnant layer compensates for the downstream reactive species concentration drop. This solves the basic problem of the apparatus that increases the batch size while improving the uniformity of the susceptor radial arrangement.

According to the invention of claim 4, the composition of a crystal film such as a silicon crystal, a SiC crystal, a GaN crystal, or a ZnO crystal can be controlled and impurities can be added.

According to the inventions according to claims 5 and 6, since the substrate can be mounted on both surfaces of the susceptor, the utilization efficiency of the CVD gas is improved, and the second problem is solved.

According to the invention which concerns on Claim 7, the crystal | crystallization of GaN and SiC can be smoothly grown on the board | substrate of sapphire and silicon which are different substrates.

FIG. 1 is a schematic diagram of the structure of a vapor phase growth apparatus disclosed in JP-A-60-090894. FIG. 2 is a schematic diagram of the structure of a vapor phase growth apparatus disclosed in JP-A-60-090894. FIG. 3 is a reprint schematic diagram of the main diagram of Japanese Patent Laid-Open No. 03-142823, which is an invention using a plurality of susceptors. FIG. 4 is a schematic diagram of the basic structure of the present invention. FIG. 5 is a schematic diagram of a first structure of a rotary radiation susceptor vapor phase growth apparatus for axial exhaust. FIG. 6 is a schematic diagram of a second structure of a rotary radiation susceptor vapor phase growth apparatus for axial exhaust.

FIG. 4 is a schematic diagram of the basic structure of the present invention. Susceptors 401 are arranged radially on a heated disc 403. The disk is graphite coated with silicon carbide. A substrate 402 is placed on both sides of the susceptor 401. The substrate 402 is housed in a pocket (not shown) and is placed stably in contact with the susceptor.

Since the number of substrates 402 can be up to twice the number of susceptors 401, twice the number of susceptors 401 is the batch size. The disc can be heated by induction heating or resistance heating. The susceptor 401 is sandwiched between heated disks 403 and 404, and is heated by the radiant heat of the two heated disks 403 and 404. The heated disk 404 is indicated by a broken line so as to make the susceptor arrangement easy to understand.

The susceptor and the disc are on the axis of rotation 405 and can rotate.

A CVD gas 406 that thermally decomposes on the substrate 402 is supplied from the periphery of the disk. It passes between adjacent susceptors and is exhausted from an exhaust hole 407. The CVD gas that has passed through the exhaust hole 407 is exhausted from an exhaust cylinder 408 at the center of the susceptor. The gas exhausted from each exhaust hole 407 is shown as a CVD gas 409 that is exhausted collectively.

The substrate 402 is heated by the radiation from the discs 403 and 404, and at the same time, the opposing substrates or susceptors also heat each other. Due to this effect, the temperature of the substrate follows that of the surrounding susceptor and disk. This acts in the direction in which the front and back temperatures of the substrate are the same, and thus has an effect of preventing warpage due to the temperature difference of the substrate 402. Since the warping of the substrate may cause cracks in the crystal film grown on the substrate, the structure of the present invention is a structure that reduces the obstacles to this crack.

Since the front and back surfaces of the susceptor are covered with the substrate, the area of the crystal film grown on the substrate is made relatively larger than the area of the crystal film grown on the susceptor. That is, it works in the direction of increasing the utilization efficiency of CVD gas.

Since the distance between adjacent susceptors becomes narrower as the gas becomes downstream, the flow velocity is faster toward the downstream. Increasing the flow rate reduces the thickness of the gas stagnant layer on the substrate, increases the growth rate, and compensates for the decrease in concentration due to the consumption of CVD gas to increase the uniformity of the growth film thickness.

The heated and pyrolyzed gas generates reactive species and grows a crystal film on the substrate, and then is exhausted from the exhaust hole 407 and does not return. This unidirectional flow prevents the reverse flow of the giant particles due to the polymerization of the reactive species downstream of the gas, and realizes the growth of only the specific reactive species determined by the temperature and heating history on the substrate. Since the gas passing through the substrate is unnecessary, the size of the exhaust cylinder 408 can be appropriately designed to shorten the gas travel distance. Further, since the film adhesion to the quartz tube that keeps airtight of these susceptors (not shown) is also prevented, there is an effect that the maintenance cycle of the quartz tube cleaning can be lengthened.

By heating the exhaust cylinder 408 and consuming the CVD gas in the cylinder, a design that can prevent adhesion to the piping and clogging of the exhaust pump is possible.

Although the susceptor arranged radially is one stage in the figure, it is possible to stack two or more stages. Further, the arrangement of the susceptors is not axially symmetric, and an extension of the surface of the susceptor crosses the outside of the rotating shaft as in a sirocco fan.

The susceptor is SiC-coated graphite, but it can also be made of SiC or AlN ceramics or quartz. The susceptor 401 can be incorporated into the disk 403 or can be produced integrally therewith.

As a first embodiment, FIG. 5 shows a schematic diagram of a first structure of a rotary radiation susceptor vapor phase growth apparatus for axial exhaust.

The structure will be described. There is a susceptor 502 on which a substrate 501 is mounted. There are 20 susceptors. 40 substrates are placed on both sides of the substrate. The susceptor 502 is integral with a heated disc 503 having a diameter of 410 cm. The susceptor 502 and the disk 503 are made of graphite, and a silicon carbide film is covered with a thickness of about 0.1 mm. The disk 503 is placed on the same axis on a heated disk 504 that also provides heat insulation. On the plurality of susceptors 502, disks 505 and 506 of the same shape are provided on the disks 503 and 504, and the susceptor 502 is heated and kept warm.

The susceptor 504 communicates with the rotation shaft 506 and can be rotated by a rotation drive 508. The graphite parts 502, 503, 504, 505 and 506 are induction heated by an induction coil 509 wound outside the quartz tube 510. The temperature can be controlled by the power supplied to the induction coil.

The inner tube 511 disposed inside the quartz tube 510 is made of quartz. A gas supplier 512 is arranged between the two tubes so as to wind the inner tube 511 in a ring shape. The gas supply unit 512 is made of graphite coated with silicon carbide. In this embodiment, three stages of grooves 513a, 513b, and 513c are cut in a ring shape inside the gas supply unit 512. Dispersed in the grooves 513b are holes 514.

A CVD gas supply pipe 515 is connected to the groove 513b. A common CVD gas supply pipe 516 is connected to the grooves 513c and 513a. The gas from the purge gas supply pipes 517, 518, 519, and 520 purges the space between the inner pipe 511 and the quartz pipe 510 to reduce the diffusion and invasion of the CVD gas, and also from the hole 514 toward the susceptor. And flows with CVD gas.

Different types of CVD gas are supplied to the CVD gas supply pipes 515 and 516 depending on the target film to be vapor-phase grown. When growing silicon, hydrogen, silane gas, and doping gas are used. Silane gas is, for example, monosilane or dichlorosilane. The doping gas is, for example, phosphine containing phosphorus (P) or diborane containing boron (B). The gas concentrations of hydrogen in the supply pipes 515 and 516 are controlled so that a uniform growth rate and impurity concentration can be obtained in the plane of the substrate.

Hydrogen or nitrogen is allowed to flow through the purge gas supply pipes 517, 518, 519, and 520.

The CVD gas from the CVD gas supply pipes 515 and 516 is thermally decomposed on the substrate on the susceptor to grow a silicon crystal film, collects in the exhaust pipe 521, and is discharged from the exhaust port 522. The exhaust pipe 521 is provided with an exhaust heater 523. The exhaust heater 523 adjusts the temperature distribution of the susceptor 502 and thermally decomposes and consumes the gas that has not reacted on the substrate. This consumption reduces the concentration of unreacted CVD gas discharged from the exhaust port 522, reduces the accumulation of by-products in the exhaust pipe behind the exhaust port, reduces the pump suction amount, and lengthens its maintenance cycle. Let

The heating temperature of the susceptor was changed according to the type of silane gas used. If the gas used is monosilane SiH 4, it decomposes at a temperature of 600 ° C. or higher. When the substrate is a silicon wafer and the crystal film grown thereon is silicon (Si), the temperature of the susceptor 502 and the temperature of the exhaust heater 523 are preferably 800 to 900 ° C. When the gas used is dichlorosilane, the temperature is preferably 900 to 1050 ° C.
The pressure was controlled by the displacement of the pump. When using the silane gas, the pressure is preferably reduced to 0.1 atm or less. A uniform film thickness distribution is easily obtained from a pressure close to atmospheric pressure.

In FIG. 5, CVD gas supply pipes 515 and 516 and purge gas supply pipes 517, 518, 519, and 520 that can be shown are shown. Any number of these gas supply pipes can be designed and arranged around the susceptor.
Although the example in which the gas supply unit 512 is made of graphite coated with silicon carbide is shown, it may be made of metal depending on the temperature range.

As a second embodiment, FIG. 6 shows a schematic diagram of a second structure of a rotary radiation susceptor vapor phase growth apparatus with axial exhaust.

A structural portion different from that of the first embodiment will be described. The susceptor 504 is rotated by a rotational drive 508 through the rotation shaft 506. The graphite parts 502, 503, 504, 505 and 506 are induction-heated by induction coils 608 and 609 accommodated in quartz ring-shaped boxes 614 and 615. The temperature can be controlled by the power supplied to the induction coil. The induction coil terminals 610, 611, 612, and 613 are taken out. The connection between the terminals is made so that the induction electromagnetic field generated by each coil is increased. The induction coil is made of copper pipe and has water. The induction coil is wound in a spiral shape, and is wound twice here. There is an induction coil near the parts 502, 503, 504, 505, and 506 to be heated, and the temperature of the part can be easily controlled by adjusting the location of the coil.

In Example 1, the structure of the device and an example of a silicon (Si) crystal film using silane gas are shown. Example 3 shows an example of crystal growth using an organometallic gas. When the organometallic gases trimethyl gallium (TMG) and ammonia (NH ₃ ) are used as the CVD gas, a crystalline film of gallium nitride (GaN) can be grown. As the substrate, a sapphire wafer (C surface), which is a different substrate, was used. As the C plane, a substrate inclined by 2 degrees from the positive direction was used. The reason for using the inclined substrate is to increase the step density (see Patent Document 3). This is an example of heterocrystal growth because the composition of the crystal film is different from the substrate. First, after evacuating and eliminating the atmosphere, nitrogen was passed through the gas supply pipes 515, 516, 517, 518, 519, and 520, and the vacuum was again applied. And the exhaust heater 523 is heated. The contaminants on the substrate surface and reaction chamber parts are hydrogenated and sublimated, and then the temperature is lowered to 500 ° C.

Trimethyl gallium (TMG) and ammonia (NH ₃ ) are allowed to flow from the CVD gas supply pipe 515 together with the hydrogen carrier. Hydrogen is allowed to flow from the other supply pipe. A 20 nm amorphous GaN grows on the substrate 502. When the CVD gas is switched to hydrogen and heated to 1000 ° C. in a hydrogen atmosphere, amorphous GaN becomes crystalline GaN particles and is formed on the substrate.

When trimethyl gallium (TMG) and ammonia (NH ₃ ) are used again as CVD gases on this state, a gallium nitride (GaN) crystal film grows with the GaN particles as nuclei.

Thereafter, when the above-described CVD gas mixed with trimethylindium (TMIn) is used, a (Ga _X In _1-X ) N crystal film corresponding to the mixing ratio grows. Further, when the above-mentioned CVD gas mixed with trimethylaluminum (TMAl) is used, a crystal film of (Ga _X Al _1-X ) N corresponding to the mixing ratio grows. When the above-mentioned CVD gas added with monosilane (SiH 4) is used, an n-type GaN crystal film grows according to the added amount. When the above-mentioned CVD gas added with Cp ₂ Mg is used, a p-type GaN crystal film corresponding to the added amount grows. Further, it is possible to design these crystal films to be arbitrarily laminated. The grown film was smooth.

Example 4 shows another example of the heterocrystal growth of silicon carbide (SiC). A silicon carbide (SiC) crystal film is grown on a silicon substrate. This is heterocrystal growth because the composition of the grown SiC crystal film and the silicon substrate are different. As the silicon substrate, a silicon substrate having a (111) plane inclined at 4 degrees in the <211> direction as a main surface was used. Here, no sign meaning minus is added to the index. The reason for tilting the axis is to provide steps on the main surface with a constant density. This technique of tilting the axis was already published in US Pat. A mixed gas of trichlorosilane (SiHCl ₃ ), propane gas (C ₃ H ₈ ), and carrier gas hydrogen (H ₂ ) was introduced. The reaction chamber pressure was controlled at a reduced pressure of 200 Pa. When the silicon substrate is heated to 1000 ° C., cubic 3C—SiC can be grown on the silicon substrate at a rate of 25 to 45 nm / min depending on the gas concentration and flow rate. The grown SiC film shows a sharp (111) X-ray diffraction peak. The surface was so smooth that electron diffraction of the streak pattern was observed.

In addition to the crystal film described above, a germanium (Ge) crystal film or a crystal film including the same can be obtained by using germane (GeH ₄ ) as a CVD gas. Although nitrogen is given as a pentavalent gas, a crystal film containing arsenic (As) can be obtained by using an arsine gas. It is also possible to obtain an oxide crystal film using a hexavalent gas instead of pentavalent gas, for example, a gas containing oxygen.

As described above, an apparatus for vapor-phase growth of a crystal film on a substrate in a large batch was manufactured.

Since the present invention can manufacture a crystal film with a large batch size at a low cost, it is suitable for a technique for manufacturing an LED or a compound semiconductor LSI at a low cost.

4 Substrate 11 Susceptor 12 Cylinder reaction chamber 13 Raw material blowing nozzle 14 Exhaust port 15 Substrate rotation introducer 16 Heater 301 Substrate 302 Susceptor 303 Rotating shaft 304 Outer cylinder 305 Work coil 306a, 306b, 306c, 306d, Gas with a blowout port Supply pipe 307 Gas exhaust pipe 308 Hole 309 Connecting rod 310 Outlet
401 susceptor 402 substrate 403 heated disc 404 heated disc 405 shaft of rotation 406 CVD gas 407 exhaust hole 408 exhaust cylinder 409 exhausted CVD gas 501 substrate 502 susceptor 503 disc 504 disc 505 disc 506 Disc 507 Rotating shaft 508 Rotation drive 509 Inductive coil 510 Quartz tube 511 Inner tube 512 Gas supply 513a, 513b, 513c Groove 514 Hole 515 CVD gas supply tube 516 Purge gas supply tube 518 Purge gas supply tube 519 Purge gas Supply pipe 520 Purge gas supply pipe 521 Exhaust pipe 522 Exhaust port 523 Exhaust heater 524 Reaction chamber lower purge gas supply pipe 525 Reaction chamber upper purge gas supply pipe 608 Inductive coil 609 Inductive coil 610 Inductive coil terminal 611 Inductive coil end 612 terminals 614 made of quartz ring-shaped box 615 quartz ring-shaped box terminal 613 induction coil of the induction coil

Claims (7)

A plurality of heated susceptors for placing a substrate on the surface are arranged in a radial manner, and a CVD film is grown on the substrate by supplying pyrolytic CVD gas from the outer periphery while rotating the susceptors in the radial arrangement. A manufacturing apparatus in which a heatable exhaust pipe is arranged at the arrangement center of a radially arranged susceptor, and a film is grown on the substrate by exhausting the CVD gas from the exhaust pipe. The manufacturing apparatus according to claim 1, wherein the susceptor is sandwiched between two or more heating disks. The manufacturing apparatus according to claim 1, wherein the heating disk is heated by induction heating. The film is a semiconductor film containing any one or more of silicon, germanium, carbon, gallium, aluminum, indium, nitrogen, oxygen, magnesium, phosphorus, arsenic, or a stacked film thereof. Item 4. The manufacturing apparatus according to Items 1 to 3. The manufacturing apparatus according to claim 1, wherein the susceptor is made of graphite. The manufacturing apparatus according to claim 1, wherein the substrate is mounted on both surfaces of the susceptor. The manufacturing apparatus according to claim 1, wherein the substrate is a sapphire or silicon substrate having an inclined axis.