JP5100231B2 - Group III nitride production equipment - Google Patents

Description

  The present invention relates to a group III nitride manufacturing apparatus using a group III halide gas and a nitrogen source gas as raw materials, which can be used for manufacturing a group III nitride film and a group III nitride bulk crystal substrate.

III-nitride _{(Al X Ga Y In 1-} X-Y N, 0 ≦ X ≦ 1,0 ≦ Y ≦ 1,0 ≦ X + Y ≦ 1) semiconductor whole area of energy band corresponding to the ultraviolet region from the visible region In addition, it has a direct transition band structure, and a highly efficient light emitting device can be manufactured. Moreover, since it has a high withstand voltage, it attracts attention as a next-generation electronic device material.

  In general, a group III nitride semiconductor device is a group III nitride formed on a single crystal substrate by a metal organic chemical vapor deposition method (MOCVD method) or a molecular beam epitaxy method (MBE method) capable of precise film thickness control. It is manufactured by forming a laminated structure of physical films.

  As a single crystal substrate material, it is difficult to obtain a substrate that is lattice-matched with a group III nitride, so sapphire, Si, etc. are mainly used, but since the lattice constant difference with the group III nitride is large, III Many threading dislocations and stacking faults are included in the group nitride film, and it is difficult to obtain a group III nitride film having high crystallinity.

  In recent years, gallium nitride (GaN) bulk substrates having high crystallinity manufactured by a halide vapor phase epitaxy (HVPE) method have been developed and used as high-quality substrates for blue light emitting devices and electronic devices.

  However, in the case of manufacturing a semiconductor device that requires a high Al composition, for example, a light emitting diode that generates ultraviolet rays of 300 nm or less, the GaN bulk substrate becomes an ultraviolet absorber, and it is difficult to obtain high luminous efficiency. Further, as the Al composition increases, a tensile stress acts in the group III nitride film on the GaN bulk substrate, so that a problem such as generation of a crack in the group III nitride film also occurs.

  In view of such a situation, an aluminum nitride (AlN) bulk substrate is being actively developed as a next-generation single crystal substrate. AlN has a band gap of about 6.0 eV, is substantially transparent to light of 210 nm or more, and has the smallest lattice constant among group III nitrides. Therefore, group III nitride laminated on an AlN substrate is used. A compressive stress is applied to the film, and a crack suppressing effect is also expected.

  Various methods such as a sublimation method, a low temperature method, a melt method, and an HVPE method have been studied as a method for manufacturing a single crystal AlN bulk substrate. In order to use an AlN bulk body manufactured by the above method as a substrate. Since it is preferable to have a thickness of at least 100 μm or more, the HVPE method that can be expected to have a high growth rate is considered to be an excellent method from the viewpoint of manufacturing.

  When an aluminum-based group III nitride crystal is grown using the HVPE method, for example, a horizontal HVPE apparatus 400 as shown in FIG. 4 is used. The apparatus shown in FIG. 4 includes a cylindrical reaction tube 410 made of a material such as cylindrical quartz glass, a heating means 420 disposed outside the reaction tube 410, and an inside of the reaction tube 410. Susceptor (substrate support base) 430. The reaction tube 410 is usually installed horizontally, and carrier gas and source gas are placed on the susceptor 430 along the length direction of the reaction tube 410 from the source gas supply means 450 located at one end thereof. A substrate (for example, a sapphire substrate) 440 is supplied so as to flow parallel to the surface of the substrate 440, and the carrier gas and unreacted reaction gas are discharged from the other end. In general, since the substrate is placed horizontally, the reaction gas also flows in the horizontal direction. Therefore, such a device is generally called a horizontal device.

  The source gas supply means 450 is a concentric triple tube nozzle structure in which a double tube 451 is inserted into a predetermined region from one end of the reaction tube, and a space inside the inner tube 452 of the double tube 451 is formed. “Group III halide gas containing aluminum halide” which is a group III element source gas diluted with a carrier gas (for example, hydrogen gas) is supplied as a passage between the outer tube 453 of the double tube 451 and the reaction tube 410. A nitrogen source gas (for example, ammonia gas) diluted with a carrier gas (for example, hydrogen gas) is supplied as a passage, and a barrier gas (for example, a space between the inner tube 452 and the outer tube 453 of the double tube is used as a passage. Nitrogen gas) gas is supplied. In the barrier gas, the group III element source gas and the nitrogen source gas immediately mix and react in the vicinity of the end of the double pipe serving as the gas discharge port, and the product generated at this time is deposited near the gas discharge port to cause the gas discharge. It is supplied to prevent the outlet from being blocked.

  Further, a substrate (for example, a sapphire substrate) 440 is placed on the susceptor 430, and the substrate is heated by a heating means, and an aluminum-based group III group is formed on the substrate 440 by a reaction between a group III element source gas and a nitrogen source gas. Nitride grows. In order to obtain a good crystal layer (growth layer), the substrate is usually heated to 1000 ° C. or higher. As a method for heating the substrate (heating means), (1) a method in which the reaction tube is directly heated by a heater attached to the outside of the reaction tube, and the substrate is heated by heat conduction or radiant heat through the reactor wall, (2) A method in which a cylindrical heating member (for example, carbon) mounted inside the reaction tube is heated by high-frequency heating from the outside of the reaction tube and the substrate is heated by radiant heat. (3) The substrate is made of carbon. A method of heating the substrate directly from the outside of the reaction tube by high-frequency heating, which is held on a substrate support stand (susceptor), (4) A method of heating the substrate by irradiating light from the outside of the reaction tube, (5) The susceptor itself There are a method in which a heating element is embedded, the susceptor is heated by energization and the substrate is heated by heat conduction, and a method (6) the susceptor and / or the substrate is heated by electromagnetic waves such as microwaves.

  By using such a horizontal apparatus, it is said that an aluminum nitride single crystal film can be formed at a rate of 100 μm / hour or more.

JP 2003-303774 A JP 2006-073578 A JP 2006-114845 A

  However, in the conventional horizontal apparatus as described above, since the susceptor is installed in a state where it is simply inserted into the reaction tube, the ratio of the source gas that does not contact the substrate surface is large, which is not economical and is not economical. The gas flow is disturbed by the collision with the side surface of the film, and it is difficult to stably grow the film.

  Such a problem is that a partition plate 212 having a hole 214 that can accommodate a susceptor is installed in the reaction tube 210 as in the apparatus 200 shown in FIG. 2, and the susceptor 230 is partitioned in the hole 214. The problem is solved by installing the upper surface of the plate and the upper surface of the susceptor so that the upper surface of the susceptor is accommodated and allowing the gas containing the source gas to circulate only in the upper space partitioned by the partition plate. It is considered possible.

  Therefore, the present inventors manufactured a device as shown in FIG. 2 and used this device to grow for a long time under the condition that a good single crystal film can be formed. An attempt was made to form a 1N single crystal film.

  As a result, the desired effect was obtained in terms of effective utilization of the source gas, but the effective AlN growth rate decreased with the passage of film formation time, and finally the effective AlN growth rate. It has become clear that there is a problem in that it becomes a state that is estimated to be zero.

  Therefore, the present invention prevents the occurrence of such a problem that occurs when a horizontal apparatus as shown in FIG. 2 is used, that is, a problem that the film formation rate decreases with time. An object is to provide a method capable of stably and efficiently producing a membrane.

  The present inventors carefully observed the situation inside the furnace after the growth of AlN in order to investigate the cause of the above problems. As a result, it was confirmed that a large amount of deposit was formed in the corner vicinity 260 of the peripheral edge of the hole of the partition plate located on the upstream side.

  The present inventors estimated the occurrence mechanism of the problem as follows from such observation results. That is, in the apparatus as shown in FIG. 2, since the susceptor is housed in a narrow space and there is no air cooling effect due to the gas flow, heat is easily trapped. It is considered that the peripheral edge of the substrate becomes a high temperature close to the substrate temperature. Crystal nuclei are more likely to be formed at corners and protrusions compared to flat parts such as the substrate surface. It can be said that it is easy to form. Then, if crystal nuclei are formed for some reason, the temperature of the portion is sufficient for crystal formation, so that crystal formation proceeds at a stretch, and finally the enlarged polycrystal or amorphous state It becomes a deposit. Furthermore, since the deposition site is a non-driven site, the deposit once formed continues to grow on the upstream side of the substrate until the end of the growth of AlN, and the supply of the raw material onto the substrate is shielded by the deposit. Therefore, it was estimated that the film formation rate on the substrate surface was reduced.

  Based on such estimation, the present inventors have made various studies on methods for suppressing crystal nucleus formation in the upstream portion of the substrate and preventing abrupt deposit formation. As a result, when the susceptor is rotated during film formation and the susceptor is provided with a heat insulating mechanism and / or a cooling mechanism so that the temperature at the peripheral edge of the susceptor is 150 ° C. lower than the substrate temperature, It has been found that the film speed can be kept stable for a long time, and the present invention has been completed.

  That is, the first present invention includes a reactor 110 having a reaction section 111, a susceptor 130 for holding a substrate, a heating means 120 for heating the substrate held by the susceptor, and a group III halide. A raw material gas supply means 150 for supplying a raw material gas comprising a combination of a gas and a nitrogen source gas into the reaction part, and supplying the raw material gas in a flow along the substrate surface, and the raw material gas in the reaction part In the group III nitride manufacturing apparatus for forming a layer made of group III nitride on the surface of the substrate heated by reacting the substrate, the reaction part has a flat bottom surface 113 having a hole 114 that can accommodate the susceptor. The susceptor 130 is rotatable about an axis perpendicular to the surface of the substrate 140 held by the susceptor as a rotation axis 131, and the susceptor 130 holds the substrate. A surface (substrate side surface) 132 is housed and installed in the hole so as to form substantially the same surface as the bottom surface, and the susceptor is made of III nitride on the heated substrate surface. A heat insulation mechanism and / or a cooling mechanism is provided to make the temperature of the peripheral edge 133 of the susceptor 150 ° C. or more lower than the temperature of the substrate during operation of forming the layer. This is a nitride manufacturing apparatus 100.

  The second aspect of the present invention is a method for producing a group III nitride using the group III nitride production apparatus of the present invention, wherein the susceptor is heated to a temperature of 1000 ° C. or higher while rotating. In this method, a layer made of a group III nitride is formed on the substrate surface, and the temperature of the outer edge of the peripheral edge in contact with the source gas is controlled to be 150 ° C. lower than the substrate temperature.

  In the apparatus of the present invention, the susceptor is housed in a hole provided in the bottom surface of the reaction part, and is installed so as not to obstruct the flow of the reaction gas. It can be narrowed and the utilization rate of the reaction gas can be increased. In addition, since the reaction gas does not collide with the side surface of the susceptor and the airflow is not disturbed, the reaction can be performed stably and the condition control can be easily performed. Further, by rotating the susceptor, the peripheral portion of the susceptor is made uniform so that local deposits are hardly enlarged, and the susceptor is provided with a heat insulating mechanism and / or a cooling mechanism. The temperature rise at the peripheral edge of the plate and the peripheral edge of the hole in the adjacent partition plate is suppressed, and the crystal growth itself is difficult to occur. It is possible to continue film formation stably.

  The group III nitride production apparatus of the present invention is similar to a conventional horizontal HVPE apparatus in that a reactor having a reaction part, a susceptor for holding a substrate, and a substrate held by the susceptor are heated. Heating means and source gas supply means for supplying a source gas comprising a combination of a group III halide gas and a nitrogen source gas into the reaction section. Then, the source gas is supplied in a flow along the substrate surface, and the source gas is reacted in the reaction portion to form a layer made of a group III nitride on the heated substrate surface.

  The apparatus of the present invention is not particularly different from the conventional horizontal HVPE apparatus, except for the features described later, and the substrate heating means and source gas supply means employed in the conventional horizontal HVPE apparatus are not limited. Can be adopted. For example, as the source gas supply means, the same means as the apparatus shown in FIG. 4, that is, means for supplying source gas and barrier gas appropriately diluted with carrier gas from a gas inlet having a concentric triple pipe structure, Can be adopted. In this means, a group III halide gas diluted with a carrier gas is supplied from the flow path at the center of the triple tube, and a nitrogen source diluted with the carrier gas from the outermost flow path as a flow path. A gas is supplied, and a barrier gas gas is supplied from an intermediate flow path between the two.

  As the group III halide gas, aluminum halide such as aluminum trichloride, gallium halide such as gallium monochloride, indium halide such as indium trichloride, or a mixture thereof can be used. These group III halide gases can be obtained by reacting a group III metal such as aluminum, gallium or indium with a hydrogen halide. The group III halide gas can also be obtained by heating and vaporizing a group III halide itself such as aluminum halide, gallium halide, or indium halide. In this case, it is preferable to use a group III halide which is an anhydrous crystal and has few impurities. When impurities are mixed in the source gas, not only defects are generated in the formed crystal, but also changes in physical and chemical characteristics are required. Therefore, it is necessary to use a high-purity product as the gas source material. When producing aluminum nitride as the group III nitride, aluminum trichloride is preferably used. In addition, since the group III halide gas may be deposited in the piping or the reaction apparatus when the gas temperature becomes 100 ° C. or lower, the gas is heated to 100 ° C. or higher, more preferably 150 ° C. or higher. It is desirable to manage.

  As the nitrogen source gas, a reactive gas containing nitrogen is adopted, but ammonia gas is preferable in terms of cost and ease of handling.

  The carrier gas and barrier gas can be a single gas of hydrogen, nitrogen, helium, or argon, or a mixed gas thereof. Impurity gas components such as oxygen, water vapor, carbon monoxide or carbon dioxide using a purifier in advance. Is preferably removed.

  As the substrate heating means, heating means (methods shown as (1) to (6) in the background art) that can be applied in the apparatus shown in FIG. 4 can be employed.

The group III nitride production apparatus of the present invention has the following features 1 to 3 as compared with the conventional horizontal HVPE apparatus.
1. The bottom surface of the reaction part is flattened, and a hole is provided in the bottom surface so that the susceptor is formed in the hole, and the surface of the susceptor that holds the substrate is substantially flush with the bottom surface. The point that was installed.
2. The point that the susceptor is rotatably installed with an axis perpendicular to the substrate surface held by the susceptor as a rotation axis.
3. A heat insulating mechanism and / or a cooling mechanism that lowers the temperature of the peripheral edge of the susceptor by 150 ° C. or more than the temperature of the substrate during operation of forming a layer made of group III nitride on the heated substrate surface. The point arranged in.

  Hereinafter, these characteristic points will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram (schematic diagram of a partial cross section) of a typical group III nitride production apparatus 100 of the present invention. The apparatus 100 is a horizontal apparatus. A partition plate 112 is installed inside a cylindrical reactor 110, and an upper space partitioned by the partition plate is a reaction unit 111. The partition plate 112 is provided with a hole 114, and a susceptor 130 is accommodated in the hole 114. The susceptor 130 is accommodated such that the substrate side surface 132 faces upward and the substrate side surface 132 and the upper surface of the partition plate 112 form substantially the same surface. Therefore, the bottom surface 113 of the reaction part is composed of the top surface of the partition plate 112 and the substrate side surface 132 of the susceptor 130. In addition, the said board | substrate side surface 132 and the partition plate upper surface form substantially the same surface refers to the state by which the unevenness | corrugation which becomes a hindrance of raw material gas distribution is excluded as much as possible, specifically, the height difference of both is high. It means 5 mm or less, preferably 2 mm or less.

  The reaction section is a space surrounded by the inner wall of the reactor and the upper surface of the partition plate, and a gas such as a raw material gas or a carrier gas supplied from the raw material gas supply means 150 flows through this space, and is sometimes called a flow channel. . The material constituting the reaction part wall surface (that is, the material constituting the reactor and the partition plate) is arbitrarily selected from materials having heat resistance against heat radiation from the susceptor and gas resistance against the source gas. Although it can be selected, quartz, SUS, AlN sintered body, AlN and BN mixed sintered body, etc. are preferably used from the viewpoint of ease of processing. When using quartz or SUS, it is necessary to pay attention not to heat the quartz to 1100 ° C. or higher and SUS to 800 ° C. or higher in consideration of the heat resistance performance of each material.

  In addition, the temperature in the reaction part can be controlled by bringing the reaction part wall surface into contact with the refrigerant flow pipe and circulating the refrigerant in the flow pipe to prevent overheating above the above temperature. This is a very useful technique.

  The susceptor 130 has a substrate platform 134 on which the substrate 140 is placed, and a peripheral portion 135 surrounding the substrate platform, and the substrate is heated inside the substrate platform 134. A carbon heating element 137 serving as the heating means 120 is embedded. The carbon heating element functions as a heater by supplying electric power from a power supply device (not shown) and energizing it.

  Moreover, it is preferable that a recess is formed on the surface of the substrate mounting portion 134 of the susceptor so that the substrate is fitted so that the substrate is not displaced. The substrate is placed in this fitting recess, but the height of the placed substrate surface is 0.01 to 0.5 mm, especially 0.05 to 0.3 mm higher than the height of the susceptor upper surface. Is preferred. Even if a deposit is slightly formed in the upstream portion of the substrate by making the height of the substrate surface slightly higher than the height of the susceptor upper surface, it is possible to reduce the influence of the reaction gas flow inhibition caused by the deposit.

  Further, the susceptor 130 is rotatably installed with an axis perpendicular to the substrate surface held by the susceptor 130 as a rotation axis 131. By performing crystal growth while rotating the susceptor, it is possible to make the state of the peripheral portion of the susceptor uniform and to disperse the nucleation sites in the circumferential direction so that local nucleation hardly occurs. The rotation of the substrate is performed using a motor (not shown).

  Furthermore, in the group III nitride manufacturing apparatus of the present invention, the temperature of the peripheral edge portion 133 of the susceptor is set during operation (during film formation) for forming a layer made of group III nitride on the heated substrate surface. A heat insulating mechanism and / or a cooling mechanism that lowers the temperature by 150 ° C. or more from the temperature of the substrate is disposed on the susceptor. As such a heat insulation mechanism and / or a cooling mechanism, (1) in the susceptor, the substrate placing part for placing the substrate immediately above and a peripheral part surrounding the substrate placing part are separated from each other. (2) a cooling device that forcibly cools the peripheral portion, and (3) a temperature of 150 ° C. or more lower than the temperature of the substrate heated at the outer peripheral corner of the peripheral portion by heat dissipation or heat insulation. The peripheral portion having a sufficient width such that can be mentioned, and these can be used in combination.

  The apparatus shown in FIG. 4 adopts the above (1) and (3). That is, as (1), an annular groove 136 is formed between the substrate platform 134 and the peripheral portion 135 to separate them. Heat is insulated by providing a groove to reduce the heat transfer area, and heating of the peripheral edge due to heat conduction from the substrate mounting portion to the peripheral edge is suppressed. The peripheral edge 135 has a sufficient width to function as (3) above. Since the heat transferred from the substrate mounting part is cooled by heat exchange with the gas flowing through the reaction part (mixed gas of carrier gas, source gas and barrier gas), the effect of (1) above, and further the substrate is rotated. Combined with the effect to be achieved, the desired effect can be achieved. The width of the peripheral portion takes into account the material of the susceptor, the amount of heat supplied to the susceptor to heat the substrate, the shape of the peripheral portion, the heat transfer area, the composition of the flow gas, the flow rate, the temperature, the rotational speed of the susceptor, etc. The temperature of the peripheral edge of the susceptor during film formation is determined to be 150 ° C. or more lower than the temperature of the substrate. The temperature at the peripheral edge of the susceptor during film formation (during operation) may be 150 ° C. or more, preferably 250 ° C. or more lower than the substrate temperature, but it prevents precipitation of group III halides in the source gas. Therefore, the lower limit is preferably 300 ° C., more preferably 400 ° C. or more. That is, the temperature at the peripheral edge of the susceptor during film formation (during operation) is preferably 300 ° C. to (substrate temperature−150 ° C.), more preferably 400 ° C. to (substrate temperature−250 ° C.). preferable.

  In addition, as the cooling device for forcibly cooling the peripheral portion of (2), a device for bringing a temperature-controlled refrigerant into contact with the back surface of the peripheral portion or a device for blowing a low-temperature inert gas on the back surface can be adopted. If such an apparatus is used, the width of the peripheral edge can be reduced.

  As a material constituting the susceptor, a material having heat resistance and ammonia resistance is preferably used. Examples of such materials include AlN sintered bodies, pyrolytic boron nitride (PBN), AlN and BN mixed sintered bodies, tantalum carbide (TaC), silicon carbide (SiC), carbon, quartz, sapphire, etc. Basic oxide ceramics such as AlN sintered body, PBN, AlN and BN mixed sintered body, TaC, and SiC in order to prevent the oxygen component in the structure from desorbing and being taken into AlN during heating. Or it is preferable to use carbon. At this time, TaC and SiC may be used as a bulk body or a coating material. When used as a coating material, for example, a TaC film or a SiC film may be formed by coating the surface of a substrate made of a different material such as a carbon substrate by a chemical vapor deposition method (CVD method) or the like. . Carbon can also be used as both a bulk material and a coating material.

  However, the material of the substrate mounting portion is restricted by what means is used as the heating means. For example, when an induction current is directly generated in the susceptor by the high frequency heating method to heat the susceptor, it is necessary to select from conductive TaC, SiC, and carbon. In addition, when heating by resistance heating or when the susceptor is overheated by heat radiation from another heating source, the presence or absence of conductivity is irrelevant to the heating method, so select from all the above materials I can do it. On the other hand, as the material of the peripheral portion, it is preferable to use a PBN, AlN and BN mixed sintered body having a relatively low thermal conductivity from the viewpoint of a heat insulating effect. The susceptor does not necessarily need to be made of a single material. For example, the substrate mounting part and the peripheral part may be made of different materials, and the peripheral part has a two-layer structure, each of which is made of different materials. You may comprise.

  When the group III nitride production apparatus of the present invention is used, even if the substrate is heated to a temperature of 1000 ° C. or higher and the group III nitride film is formed, the susceptor is rotated and further contacted with the source gas Since the temperature of the outer edge of the peripheral edge can be controlled to be 150 ° C. lower than the substrate temperature, crystal growth at the peripheral edge of the susceptor and the peripheral edge of the partition plate adjacent to the susceptor is suppressed, and the product is manufactured for a long time. Even if the film is formed, the film formation can be continued stably without a rapid decrease in the film formation rate.

  When producing a group III nitride using the group III nitride production apparatus of the present invention, the substrate is first held in a susceptor, and then the susceptor is rotated, and the substrate is heated to about 1000 ° C. in a hydrogen atmosphere. After cleaning, the flow of the raw material gas is started, and a layer made of a group III nitride may be formed on the heated substrate. At this time, the rotation speed of the susceptor is preferably 10 to 4000 rpm, particularly 50 to 500 rpm. Further, the substrate temperature at the time of forming a layer made of a group III nitride (during film formation) is preferably 1000 to 1700 ° C., particularly 1250 to 1500 ° C. The growth time may be determined in a timely manner based on the growth rate so as to obtain a desired film thickness. After a predetermined time has elapsed, the supply of the source gas is stopped, the susceptor is cooled to room temperature, and the substrate is removed from the reactor. Just take it out.

  EXAMPLES Hereinafter, the content of the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples.

Example 1
An AlN single crystal was manufactured using an apparatus having a structure as shown in FIG. The used susceptor has a substrate mounting portion and a peripheral portion, and a groove is provided between them. The substrate mounting portion and the peripheral portion are both made of PBN, and a carbon heating element is embedded in the substrate mounting portion, and the substrate can be heated by energizing the carbon heating element.

  The manufacture of the AlN single crystal was performed according to the following procedure. That is, first, the sapphire C-plane substrate was held on the susceptor, and the susceptor was rotated at 100 rpm. Next, while flowing hydrogen at a flow rate of 10 slm, the sapphire substrate was heated to 1200 ° C. and held for 10 minutes to clean the surface. Thereafter, the flow of the source gas was started while maintaining the rotation state of the susceptor and the substrate temperature. At this time, the flow rates of the source gas and the barrier gas were aluminum trichloride 5 ssccm, ammonia 20 sccm, and nitrogen (barrier gas) 1500 sccm, and the total flow rate was adjusted to 10 slm by adjusting the flow rate of the carrier gas (hydrogen). The pressure in the reaction part was set to 500 Torr.

  The aluminum trichloride used as the group III source gas was generated and supplied by reacting metal aluminum heated to 500 ° C. and hydrogen chloride gas upstream of the reaction furnace. Moreover, in order to prevent precipitation of aluminum trichloride in the pipe, the pipe from the reaction furnace for reacting metal aluminum and hydrogen chloride to the reaction section was heated to 200 ° C.

  After film formation for a predetermined time, only the supply of aluminum trichloride was stopped and film formation was completed. The film formation was performed four times while changing the film formation time from 60 minutes, 120 minutes, 360 minutes, and 600 minutes. When the temperature of the outer peripheral region of the susceptor peripheral edge during film formation was measured with an infrared radiation thermometer, the temperature was about 980 ° C. in all cases.

  After stopping the supply of aluminum trichloride, after confirming that the susceptor temperature became 700 ° C. or less, the supply of ammonia was stopped, the gas supplied into the reaction part was switched to nitrogen gas, the interior of the furnace was replaced with nitrogen, Then, the substrate was taken out. The central portion of the substrate thus taken out was opened to a 5 mm square, and then coated with 10 nm of Pt by a sputtering coater. Then, film thickness evaluation was performed by observing the cross section of a sample with a scanning electron microscope (SEM). The film thicknesses were 42 μm, 78 μm, 235 μm, and 397 μm at the growth time of 60 minutes, 120 minutes, 360 minutes, and 600 minutes, respectively. FIG. 3 shows a plot of the thickness of the obtained AlN single crystal film against the growth time.

Comparative Example 1
The apparatus having the structure shown in FIG. 2, that is, a susceptor similar to the susceptor used in Example 1 is used except that the susceptor does not have a peripheral portion and a groove and is fixedly installed so as not to rotate. The same operation as in Example 1 was performed. The film thicknesses were 40 μm, 77 μm, 190 μm, and 230 μm at the growth time of 60 minutes, 120 minutes, 360 minutes, and 600 minutes, respectively. FIG. 3 shows a plot of the thickness of the obtained AlN single crystal film against the growth time. The temperature at the peripheral edge of the susceptor at the time of film formation is about 1160 ° C., which is nearly 200 ° C. higher than in Example 1. After film formation for 360 minutes or more, the temperature at the peripheral edge of the partition plate hole at the upstream portion of the susceptor is Crystalline deposits were attached near the corners.

Comparative Example 2
In Example 1, film formation was performed for 600 minutes in the same manner except that the susceptor was not rotated. The film thickness of the obtained film was 310 μm, and the inside of the apparatus was observed after the film formation. As a result, crystalline deposits were attached in the vicinity of the corner of the peripheral edge of the partition plate upstream of the susceptor.

This figure is a schematic diagram (schematic diagram of a partial cross section) of a typical group III nitride production apparatus of the present invention. This figure is a schematic diagram (schematic diagram of a partial cross section) of the group III nitride production apparatus used in Comparative Example 1. This figure is a graph showing the relationship between the film thickness of the obtained AlN single crystal film and the film formation time in Example 1 and Comparative Example 1. This figure is a schematic diagram (schematic diagram of a partial cross section) of a conventional horizontal HVPE apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Group III nitride manufacturing apparatus 110 ... Reactor 111 ... Reaction part 112 ... Partition plate 113 ... Bottom 114 ... Hole 120 ... Heating means 130 ... Susceptor 131 ... Rotary shaft 132 ... Substrate side surface 133 ... Rim edge part 134 ... Substrate placement part 135 ... Rim part 136 ... Groove 137 ... Carbon heating element 140 ... Substrate 150 ... Raw material gas supply means 200 ... Group III nitride production apparatus 210 ... Reactor 211 ... Reaction section 212 ... Partition plate 213 ... Bottom 214 ... Hole 220 ... Heating means 230... Susceptor 237... Carbon heating element 240... Substrate 250 .. source gas supply means 260 .. vicinity of corner of peripheral edge of partition plate hole 400. Apparatus 410 ... reaction tube 420 ... heating Stage 430 · susceptor 440 ... substrate 450 ... source gas supply means 451 ... double tube 452 ... outer tube between the inner tube 453 ... double between double

Claims (6)

A reactor gas having a reaction part, a susceptor for holding the substrate, a heating means for heating the substrate held by the susceptor, and a source gas comprising a combination of a group III halide gas and a nitrogen source gas A source gas supply means for supplying the reaction gas into the reaction section, and supplying the source gas in a flow along the substrate surface and reacting the source gas in the reaction section to heat the group III on the substrate surface. In a group III nitride manufacturing apparatus for forming a layer made of nitride,
The reaction portion has a flat bottom surface having a hole that can accommodate the susceptor, and the susceptor is rotatable about an axis perpendicular to a substrate surface held by the susceptor as a rotation axis. The surface holding the substrate is housed and installed in the hole so that the surface on the side of the substrate is substantially the same as the bottom surface, and the susceptor has a group III nitride on the heated substrate surface. A heat-insulating mechanism and / or a cooling mechanism is provided to make the temperature of the peripheral edge of the susceptor 150 ° C. or more lower than the temperature of the substrate during operation of forming a layer made of a material III Group nitride production equipment. Insulation mechanism and / or cooling mechanism,
(1) In the susceptor, a groove formed so as to separate a substrate mounting portion on which the substrate is mounted and a peripheral portion surrounding the substrate mounting portion from each other,
(2) a cooling device that forcibly cools the peripheral edge, and (3) a sufficient width so that the temperature of the outer peripheral corner of the peripheral edge is 150 ° C. or more lower than the temperature of the substrate heated by heat dissipation or heat insulation. The group III nitride manufacturing apparatus according to claim 1, wherein the apparatus is at least one selected from the group consisting of the peripheral portions. 3. The group III nitride manufacturing apparatus according to claim 1, wherein surfaces of the substrate mounting portion and the peripheral portion on which the substrate is mounted are made of non-oxide ceramics or carbon. 4. The group III nitride manufacturing apparatus according to claim 1, wherein the heating of the substrate by the heating unit is performed by generating heat in a portion of the susceptor located below the substrate. 5. The group III nitride manufacturing apparatus according to any one of claims 1 to 4, wherein a combination of aluminum trichloride and ammonia is used as a source gas, and an aluminum nitride single crystal layer is formed as a layer made of group III nitride. 6. A method for producing a group III nitride using the group III nitride production apparatus according to claim 1, wherein the substrate surface is heated to a temperature of 1000 ° C. or higher while rotating the susceptor. And forming a layer made of a group III nitride, and controlling the temperature of the outer edge of the peripheral edge in contact with the source gas to be lower by 150 ° C. or more than the substrate temperature.

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