JP2008088048A - Method and apparatus for producing group-iii nitride - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a group-III nitride, such as an aluminum-based group-III nitride, having a quality as good as that produced by conventional methods with a high yield, by growing a group-III nitride by an HVPE method, and an apparatus used for the production method. <P>SOLUTION: There is provided a method for producing a group-III nitride in which a group-III halogenated gas, such as an aluminum trichloride gas, is reacted with a nitrogen source gas, such as an ammonia gas, in a deposition chamber 41 to grow a group-III nitride on a substrate 43 held in the deposition chamber. In the method, the group-III halogenated gas and the nitrogen source gas are mixed with each other in advance to form a mixed gas, then they are introduced into the deposition chamber 41 without substantially producing a deposition substance in the gas by a method such as to control the temperature at the time of gas mixing and introduction and reacted with each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a Group III nitride by vapor phase growth using a Group III halide gas as a raw material.

  Group III nitride semiconductor crystals such as aluminum nitride, gallium nitride, and indium nitride have a wide range of band gap energy values, which are about 6.2 eV, about 3.4 eV, and about 0.7 eV, respectively. . These group III nitride semiconductors can form mixed crystal semiconductors having an arbitrary composition, and can take values between the above band gaps depending on the mixed crystal composition.

  Therefore, by using a group III nitride semiconductor crystal, it is possible in principle to produce a wide range of light emitting elements from infrared light to ultraviolet light. In particular, in recent years, development of light-emitting elements using aluminum-based group III nitride semiconductors (mainly aluminum gallium nitride mixed crystals) has been vigorously advanced. By using aluminum group III nitride semiconductors, it is possible to emit light with a short wavelength in the ultraviolet region. Ultraviolet light emitting diodes for white light sources, ultraviolet light emitting diodes for sterilization, lasers that can be used for reading and writing high density optical disk memories, lasers for communication A light emitting light source such as can be manufactured.

  A light-emitting device using an aluminum-based group III nitride semiconductor (also referred to as an aluminum-based group III nitride semiconductor light-emitting device) is a semiconductor single crystal thin film having a thickness of several microns on a substrate, similar to a conventional semiconductor light-emitting device. (Specifically, a p-type semiconductor layer, a light-emitting layer, and a thin film that becomes an n-type semiconductor layer) can be stacked in order. Such a thin film of a semiconductor single crystal can be formed by using a crystal growth method such as a molecular beam epitaxy (MBE) method or a metalorganic vapor phase epitaxy (MOVPE) method. Thus, studies have also been made to form a laminated structure suitable as a light-emitting element by adopting such a method for an aluminum-based group III nitride semiconductor light-emitting element.

  Currently, a sapphire substrate is generally used as a substrate used for an ultraviolet light-emitting element from the viewpoint of crystal quality as a substrate, ultraviolet light transmittance, mass productivity, and cost. However, when a sapphire substrate is used, there arises a problem due to a difference in physical properties between the sapphire substrate and aluminum gallium nitride forming a semiconductor multilayer film.

  For example, when the lattice constants of the substrate and the semiconductor multilayer film are different, crystal defects called misfit dislocations are introduced into the semiconductor multilayer film. Furthermore, due to the difference in thermal expansion coefficient between the growth layer and the substrate, during the process of lowering the temperature from the deposition temperature of the semiconductor multilayer film during the production of the semiconductor multilayer film, the growth layer or the substrate is caused by the difference in thermal expansion coefficient. Cracks and warping occur. Due to such dislocations and cracks, the light emitting performance of the semiconductor laminated film is degraded.

  In order to solve these problems, various devices have been devised in the film formation conditions and structure of the semiconductor multilayer film, but in order to essentially solve the above problems, the semiconductor multilayer film It is ideal to use a substrate that is close to the lattice constant of and has a small difference in thermal expansion coefficient. An aluminum-based group III nitride single crystal substrate, that is, an aluminum nitride single crystal substrate or an aluminum gallium nitride single crystal substrate can be said to be an optimal substrate material. However, the aluminum-based group III nitride single crystal substrate is not in a state where a large-area and homogeneous substrate can be stably manufactured at present, and if the high-quality aluminum-based group III nitride single crystal substrate can be manufactured, the above problem Is expected to contribute greatly to the improvement of light emitting device performance and the practical application of ultraviolet light sources.

  Since a thickness of at least 100 μm is required to use an aluminum-based group III nitride single crystal as a substrate, a substrate made of an aluminum-based group III nitride single crystal is manufactured using the above-described crystal growth method with a slow film formation rate. It is not practical to do.

  A hydride vapor phase epitaxy (HVPE) method is known as a method for growing an aluminum-based group III nitride single crystal having a high deposition rate (see Patent Documents 1 to 3). The HVPE method is difficult to control the film thickness more precisely than the MBE or MOVPE method, so it is not suitable for forming a crystal layer of a semiconductor light-emitting device. It is possible to obtain. Therefore, the HVPE method makes it possible to mass-produce a substrate made of an aluminum-based group III nitride single crystal that cannot be obtained by the conventional MBE method or MOVPE method at a practical level. In the case of growing an aluminum-based group III nitride crystal using the HVPE method, for example, a vapor phase growth apparatus as shown in FIG. 1 is used. The apparatus shown in FIG. 1 includes a reactor body composed of a cylindrical quartz glass growth chamber (reaction tube) 11, heating means 12 disposed outside the growth chamber 11, and the growth chamber 11. A substrate support (hereinafter also simply referred to as a “susceptor”) 13, supplying a carrier gas and a source gas from one end of the growth chamber 11, and a carrier gas and an unreacted reaction from the other end. It is structured to discharge gas.

  The growth chamber on the source gas supply side has a concentric triple tube nozzle structure in which a triple tube is inserted into a predetermined region from the end, and a carrier gas (with a space inside the inner tube 15 of the triple tube as a passage) For example, a group III halide gas containing aluminum halide which is a group III element source gas diluted with hydrogen gas is supplied, and a carrier gas (for example, a space between the middle tube 16 and the outer tube 17 of the triple tube is used as a passage. A nitrogen source gas (for example, ammonia gas) diluted with hydrogen gas) is supplied, and a barrier gas (for example, nitrogen gas) is supplied through the space between the inner tube 15 and the intermediate 16 as a passage. 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.

A substrate (for example, a sapphire substrate) 14 is placed on the susceptor 13, and the substrate is heated by heating means, and an aluminum-based group III nitride is formed on the substrate 14 by a reaction between a group III element source gas and a nitrogen source gas. Things grow. The substrate is usually heated to 1000 ° C. or higher in order to obtain a good crystal layer (growth layer).
As a method for heating the substrate, (1) a method in which the growth chamber is directly heated by a heater attached outside the growth chamber, and the substrate is heated by heat conduction or radiant heat through the reactor wall; (2) growth A method in which a cylindrical heating member (for example, carbon) mounted inside the chamber is heated from outside the growth chamber by high-frequency heating and the substrate is heated by radiant heat. (3) The substrate is supported by a carbon substrate. (4) A method of heating the substrate by irradiating light from the outside of the growth chamber, (4) A method of heating the susceptor by high-frequency heating from the outside of the growth chamber and heating the substrate by the heat conduction. 5) There are a method in which a heating element is embedded in the susceptor itself, the susceptor is heated by energization, and the substrate is heated by heat conduction, and (6) the susceptor and / or the substrate is heated by electromagnetic waves such as microwaves.

  As a technique similar to the present invention, there is a method of generating aluminum nitride particles from an aluminum trichloride gas and an ammonia gas by heating by an external heating method having a maximum temperature of about 1100 ° C. (see Non-Patent Document 1). Similarly, in the present invention, ammonia gas is used as a halide gas and a nitrogen source gas, but the range of the gas supply temperature, the pipe heating temperature during gas transportation, etc. is more precisely limited, and the substrate is further up to 2000 ° C. This is a method for producing a single crystal or a polycrystalline bulk crystal on the substrate by heating, and it is an invention having a dimension different from that of simply producing a solid powder by reacting a raw material gas.

JP 2003-303774 A JP 2006-073578 A JP 2006-114845 A Journal of American Ceramics Society 77 [8] 2009-2016 (1994)

  When the aluminum-based group III nitride was produced by the HVPE method using the conventional vapor phase growth apparatus shown in FIG. 1, the yield was less than 10%, and the productivity was not necessarily sufficient. The yield mentioned here is the ratio (% by weight) of the group III metal-based aluminum-based group III nitride immobilized on the substrate with respect to the supplied group III source gas.

  The present invention is a method for producing a group III nitride such as an aluminum-based group III nitride by the HVPE method, which has a good quality equivalent to that of the conventional method and has a high yield, that is, high productivity. The purpose is to provide.

  The present inventors diligently studied to solve the above problems. As a result, when the group III source gas and the nitrogen source gas are separately introduced into the growth chamber and both gases are mixed in the growth chamber, the nozzles are mixed so that both gases are uniformly mixed before reaching the substrate. It was found that the yield was reduced because the mixed gas did not effectively contact the substrate.

  The inventors considered that the yield could be improved if both raw material gases were mixed in advance and then sprayed in the vicinity of the substrate, and when the method was attempted, solid components were found in the piping and nozzle nozzles. It has been revealed that a new problem arises that the group III nitride cannot be grown substantially on the substrate.

  Therefore, when the reactivity of the mixed gas of the group III source gas and the nitrogen source gas was examined, when a group III halide gas was used as the group III source gas, the mixed gas with the nitrogen source gas was used. Occasionally, it was necessary to maintain a stable state without generating precipitates and the conditions were found, and the present invention was completed.

  That is, the first invention includes a growth process in which a group III nitride gas and a nitrogen source gas are reacted in a growth chamber to grow a group III nitride on a substrate held in the growth chamber. The method for producing a product further comprises a premixing step of premixing the group III halide gas and the nitrogen source gas before introducing them into the growth chamber, and the mixed gas obtained in the premixing step includes In the method for producing a group III nitride, the precipitate is introduced into the growth chamber without substantially generating a precipitate in the gas.

  In the above method, for example, when the supply partial pressure of the Group III halide gas to be supplied is P (atm), the temperature T (° C.) when mixing the Group III halide gas and the nitrogen source gas in the premixing step. Is performed at a temperature not lower than the lower limit temperature specified by the mathematical formula (1) and lower than 600 ° C., and then the obtained mixed gas is introduced into the growth chamber while maintaining the temperature not lower than the lower limit temperature and lower than 600 ° C. Since it can be introduced into the growth chamber without being substantially generated and sprayed directly onto the substrate, the yield can be greatly improved.

  The temperature range is as shown in FIG. 2, when aluminum trichloride gas is used as the group III halide gas and ammonia gas is used as the nitrogen source gas. Determined based on the results of a reference experiment (discussed below) that investigated whether solids were deposited when mixed gas was formed and circulated in the soaking zone under various conditions with the temperature of the zone as a parameter. It is a thing.

  The lower limit of the temperature range in which the mixed gas can be kept stable corresponds to the deposition temperature of the adduct of the group III halide gas and the nitrogen source gas (also referred to as an adduct), and the upper limit is the group III nitride formation temperature. Corresponding. In particular, the lower limit may be affected by the concentration of the mixed gas or the pressure of the entire mixed gas. However, if the supply partial pressure of the halogen gas of the group III element to be supplied is P (atm) and the temperature is T (° C.), it should be within the temperature range of not less than the lower limit temperature defined by Equation (1) and less than 600 ° C. For example, in many mixed systems including an aluminum trichloride-ammonia system, the mixed gas can be kept stable without causing precipitation.

  A second invention is a growth chamber comprising a gas inlet for introducing a group III halide gas and a nitrogen source gas, a gas outlet, a susceptor for holding the substrate, and a heating means for heating the substrate. An apparatus for producing a group III nitride, further comprising a gas introduction nozzle and a gas mixer having a temperature control function, the gas introduction nozzle being mounted downstream of the gas mixer Furthermore, the gas mixer is a group III nitride production apparatus characterized in that upstream of the gas mixer, the gas mixer is connected to each gas inlet for introducing a group III halide gas and a nitrogen source gas.

  According to the present invention, it is possible to produce a group III nitride having a good quality equivalent to or better than that of the conventional HVPE method, particularly an aluminum-based group III nitride crystal with a higher yield, that is, higher productivity. .

  The apparatus of the present invention is suitable for the production of group III nitrides using the above-described method of the present invention, and the apparatus itself is characterized in that the structure is simple and compact compared to conventional apparatuses. . This is because when the raw material gases are introduced separately, a space of a certain degree or more is required between the nozzle and the substrate in order to uniformly mix the two raw material gases. This is because the raw material gas can be blown in the vicinity of the substrate, so that such a space is not necessary. Further, in the apparatus of the present invention, since the reaction for generating the group III nitride occurs efficiently on the substrate, it is not necessary to heat the entire apparatus if the substrate is heated. There is also an advantage that the heating device can be omitted.

  In the method of the present invention, a group III nitride is produced by causing a group III halide gas and a nitrogen source gas to react in a growth chamber and growing a group III nitride on a substrate held in the growth chamber. . Here, group III nitride and group III halide mean nitride and halide of group III element, respectively, and group III element means an element belonging to group III (or group 13) of the periodic table, that is, , B, Al, Ga, In, and Tl means at least one element selected from the group consisting of Tl.

  The method of the present invention and the apparatus of the present invention will be described below with reference to the drawings.

  FIG. 4 shows a schematic diagram of a representative apparatus of the present invention. The apparatus shown in FIG. 4 includes a gas inlet 48 for introducing a group III halide gas and a nitrogen source gas, a gas outlet 49, a susceptor 42 for holding the substrate, and a heating means for heating the substrate. The growth chamber 41 is provided. It is possible to install an external heating device similar to the external heating device 12 in FIG. 1 outside the growth chamber 41 to supplementarily heat the substrate from the outside, but this device is not necessarily required.

  As a material for the growth chamber 41, a material made of a corrosion-resistant metal such as graphite, stainless steel, Inconel, Hastelloy or the like can be used, but quartz glass is preferable from the viewpoint of reducing contamination from the wall surface. When metal is used, contamination from the metal casing can be prevented by maintaining the temperature of the contact surface with the gas at about room temperature using a water cooling jacket or the like.

  The susceptor 42 has a substrate holding surface, and can hold the substrate 43 on the surface. As the substrate 43, a crystal substrate such as sapphire, silicon, silicon carbide, zirconium boride, gallium arsenide, gallium phosphide, zinc oxide, gallium nitride, or aluminum nitride is used. Furthermore, a template substrate in which a thin aluminum nitride crystal layer is stacked on a base material substrate such as sapphire can also be used.

  In the apparatus shown in FIG. 4, a heat-generating antibody is embedded in the susceptor 42 and functions as a heater for heating the substrate. As heating means for heating the substrate, various heating methods such as high-frequency induction heating and optical heating, which are employed in the conventional apparatus shown in FIG. 1, can be used.

  As a material of the susceptor 42, nitrides such as boron nitride and aluminum nitride can be preferably used. In order to give the susceptor a function as a heater, a heating resistor may be embedded in the susceptor body, or a heating resistor may be joined to the back surface of the susceptor body, and power may be supplied to the heating resistor from the outside. As the heating resistor, carbon (C), tungsten (W), molybdenum (Mo), tantalum (Ta) or the like that does not melt at the operating temperature is used.

  The material constituting the susceptor body is not particularly limited as long as it is a material that is stable at the operating temperature and hardly corroded by a group III halide gas, but at least the entire surface on which the substrate is placed can be heated uniformly. Therefore, it is preferable to use a nitride having high thermal conductivity, that is, the above aluminum nitride or boron nitride.

  The apparatus shown in FIG. 4 further includes a gas introduction nozzle 47 having a temperature adjustment function, a line mixer 50, and a gas mixer 46. Further, the gas mixer 46 is connected to a group III halide gas supply source (not shown) via a pipe 44 and a gas inlet 48 upstream thereof, and via a pipe 45 and a gas inlet 48. To a nitrogen source gas supply source (not shown).

  The present invention is characterized in that the group III halide gas and the nitrogen source gas are mixed in advance and then introduced into the growth chamber. For this reason, the apparatus used in the present invention is provided with a gas mixer for mixing the two kinds of source gases upstream of the gas introduction nozzle 47.

  The gas mixer is an instrument that joins two or more types of gas flow paths to convert them into one gas flow path, and the shape is not particularly limited as long as a plurality of types of gas can be mixed using the instruments.

  As a specific mixer mode, for example, when two types of gas flow paths are merged and converted into one gas flow path, the pipes connected in a T-shape or Y-shape are connected. Plumbing can be suitably used. In addition, when the three types of gas flow paths are merged and converted into one gas flow path, a pipe connected in a cross shape can be preferably used. Alternatively, the third gas distribution path may be merged after the two types of gas distribution paths are merged into one.

  The group III halide gas and the nitrogen source gas joined together in the gas mixer are mixed until they are ejected from the gas introduction nozzle 47, but the mixing is mainly performed by the action of diffusion. It is desirable that the passage time required to reach the tip of the gas introduction nozzle after being merged into the gas mixer is 0.01 seconds or more.

  As a more preferred embodiment, it is preferable to further promote the mixing by installing a line mixer 50 on the downstream side joined to one gas flow path by the gas mixer. A line mixer is one in which wings for mixing are installed inside a gas flow path such as piping, and a plurality of types of gas are forced to be disturbed by the wings while passing through the line mixer 50 and mixed. Is to be done. By using a line mixer, it is possible to mix a plurality of types of gas within a short time during gas transportation.

  The gas mixer 46 and the line mixer 50 are preferably capable of controlling the temperature of the mixed gas. In addition to a method of winding a ribbon heater around the gas mixer, a method of heating a liquid heat medium to a target temperature around the gas mixer can be used. When the supply partial pressure of the halogen gas of the group III element to be supplied is P (atm), the temperature T (° C.) is controlled to a temperature not lower than the lower limit temperature defined by the equation (1) and lower than 600 ° C. Prevents precipitation of solids inside the vessel.

  As the material of the gas mixer, a corrosion-resistant metal pipe such as stainless steel or Inconel, a quartz glass pipe, or the like can be used. In order to perform piping heating, it is preferable to use one having good chemical durability.

  The gas mixer 46 is connected to a group III halide gas supply source (not shown) via a pipe 44 and a gas inlet 48 upstream of the gas mixer 46, and is controlled by a flow rate adjusting means such as a mass flow controller disposed in the middle of the pipe. A gas having a predetermined flow rate can be supplied. Similarly, the gas mixer 46 is connected to a nitrogen source gas supply source (not shown) via a pipe 45 and a gas inlet 48 upstream thereof, and the flow rate of a mass flow controller or the like disposed in the middle of the pipe is adjusted. A gas having a predetermined flow rate can be supplied by the means.

  As the Group III halide gas, it is preferable to use an aluminum halide gas or a mixed gas of an aluminum halide gas and a group III element halide gas other than aluminum. Since the halide has a high saturated vapor pressure, the amount of raw material supplied to the substrate can be increased, and high-speed growth is possible.

  The type of aluminum halide gas is not particularly limited. However, when quartz glass is used in a portion in contact with the reaction gas, it is preferable to use aluminum trichloride gas because of its low reactivity with quartz glass. Moreover, as a gas of a halide of a group III element other than aluminum, a gas of gallium chloride or boron chloride can be used.

  When a mixed gas of an aluminum halide gas and a halide gas of a group III element other than aluminum is used as the group III halide gas, the composition depends on the target mixed crystal composition of the aluminum group III nitride. Can be set as appropriate. However, in this case, since the reaction rate differs from the nitrogen source gas depending on the type of group III element, the supply ratio of group III halide gas may not directly correspond to the mixed crystal composition. It is preferable to investigate the relationship between

  The group III halide gas can be obtained by reacting a group III metal such as aluminum, gallium or indium with hydrogen halide or chlorine gas. For example, as described in Japanese Patent Application Laid-Open No. 2003-303774, the gas generated from the reactor for performing the above reaction can be used as it is as a group III halide gas supply source.

  The group III halide gas can also be obtained by heating and vaporizing a solid or liquid group III halide such as aluminum halide, gallium halide, indium halide or the like. In this case, the Group III halide is preferably an anhydrous crystal and high purity. When impurities are mixed in the source gas, not only defects are generated in the formed crystal, but also physical properties, chemical properties, and electrical properties may be changed.

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

  It is preferable that the group III halide gas and the nitrogen source gas are each diluted to a desired concentration with a carrier gas and introduced into the gas mixer. At this time, hydrogen, nitrogen, helium, or a single gas of argon, or a mixed gas thereof can be used as a carrier gas, and an impure gas component such as oxygen, water vapor, carbon monoxide, or carbon dioxide using a purifier in advance. Is preferably removed.

In the present invention, the group III halide gas and the nitrogen source gas are premixed before being introduced into the growth chamber, and the mixed gas obtained in the premixing step is substantially mixed with precipitates in the gas. Introduction into the growth chamber without generation is an important requirement, and specific conditions for realizing such a state can be determined based on the results of the following reference experiments.
[Reference experiment]
In the apparatus shown in FIG. 2, a group III halide gas introduction nozzle 22 is installed on one side of a quartz reaction tube 21 having an inner diameter of 20.5 mm, and a group III halide gas is introduced from the inside of the group III halide gas introduction nozzle 22. It is diluted with a carrier gas (hydrogen gas) and supplied. A barrier nozzle 23 for circulating a nitrogen gas flow (so-called barrier gas) concentrically around the group III halide gas nozzle 22 is further installed. Further, from the outside of the barrier gas nozzle, a nitrogen source gas is diluted with a carrier gas (hydrogen gas) and supplied. The supplied group III halide gas, barrier gas, nitrogen source gas, and carrier gas are mixed in the quartz reaction tube 21. Group III halide gas and nitrogen source gas react and pass through a soaking zone with a total length of 150 mm.

In the reference experiment, the soaking region was heated in the range of 100 to 650 ° C. by an external heating device. The group III halide gas and the carrier gas (hydrogen gas) are supplied from the group III halide gas introduction nozzle 22 so that the total is 300 sccm (Standard Cubic Centimeter per Minute), and the barrier nozzle 23 is supplied with nitrogen gas of 50 sccm, Various gases were supplied from the surroundings so that the nitrogen source gas and the carrier hydrogen gas totaled 300 sccm, and the total gas flow rate after mixing was 650 sccm. The pressure in the growth chamber at this time was 1 atm. Aluminum trichloride gas as group III halide gas was supplied in a range of 9 × 10 ⁻³ to 1 × 10 ⁻⁴ atm of partial pressure with respect to the total gas flow rate. As a method for generating aluminum trichloride, as disclosed in Patent Document 1, a method of reacting metal aluminum and hydrogen chloride gas at 500 ° C. was used. In addition, ammonia gas was used as the nitrogen source gas, and a flow rate that was four times the supply partial pressure of the aluminum trichloride gas supply partial pressure was supplied. After supplying these gases for a time range of 10 to 30 minutes, the supply and heating were stopped and the state of solid precipitation in the growth chamber was observed sequentially to determine the reaction temperature and raw material concentration conditions at which solid precipitation did not occur. .

  As a result, the region in which solid precipitation did not occur when the aluminum trichloride supply partial pressure and the reaction temperature were used as parameters was shown in FIG.

  In the figure, the ◯ marks indicate conditions where no solid precipitation occurred, and the X marks indicate conditions where solid precipitation was observed. It is clear that solid precipitation generally does not occur in the temperature range of 150 ° C or higher and lower than 600 ° C, but the conditions under which solid precipitation is seen at the minimum temperature are also affected by the supply pressure of aluminum trichloride gas. When the supply partial pressure of the halogen gas of the Group III element supplying this is P (atm) and the temperature is T (° C.), the lower limit temperature is approximated by the relational expression shown in Equation (1). It was possible to express it. Below the lower limit temperature, a white solid precipitate was observed on the growth chamber wall.

  The lower limit of the temperature range in which the mixed gas can be kept stable is the precipitation of an adduct (also called an adduct) in which a group III halide gas (aluminum trichloride gas) and a nitrogen source gas (ammonia gas) are chemically bonded. The lower limit may be affected by the concentration of the mixed gas or the pressure of the entire mixed gas, but the effect of the present invention is maintained by maintaining the temperature at the lower limit or higher according to the relational expression of the formula (1). Can be suitably obtained. On the other hand, at 600 ° C. or higher, a white solid precipitate was observed on the growth chamber wall, and the precipitate at this temperature was aluminum nitride.

  When mixing the Group III halide gas and the nitrogen source gas and transporting the pipe to the nozzle 47, the gas mixer and the pipe are heated, and the temperature of the mixed gas is controlled to the lower limit temperature or higher and lower than 600 ° C. shown in Formula (1). It is preferable to do this. When the temperature of the mixed gas is lower than the lower limit temperature shown in the mathematical formula (1), the group III halide gas supplied as a raw material is likely to be solid precipitated. On the other hand, when the temperature is 600 ° C. or higher, the group III halide gas which is a mixed gas and the nitrogen source gas react to generate a group III nitride. For these reasons, if solids are deposited in the pipe, the gas composition changes and the production conditions of the group III nitride become unstable, and the pipe is blocked and the production of the group III nitride itself becomes difficult.

  For this reason, in order to control the temperature of the mixed gas in the gas mixer 46 to the said range, the piping 44 and the piping 45 are heated, and the gas temperature to distribute | circulate is more than the minimum temperature shown by Numerical formula (1), and below 600 degreeC. It is preferable to control. The gas mixer and the pipe can be heated by winding a ribbon heater in which a heating element is embedded in fiber or resin. Further, a jacket through which the liquid heat medium flows may be provided in the mixer or the pipe, and a liquid such as oil whose temperature is controlled to be constant may be circulated in the jacket.

  The gas introduction nozzle 47 has a temperature adjustment function for introducing the mixed gas of the group III halide gas and the nitrogen source gas mixed by the gas mixer 46 into the growth chamber 41 in a stable state so as not to precipitate solids. Have The temperature of the gas introduction nozzle 47 can be suitably adjusted by providing a jacket through which the liquid heat medium flows in the nozzle and circulating a liquid such as oil whose temperature is controlled to be constant in the jacket.

  As an example of the liquid heat medium, dibenzyltoluene can be used for heating up to 350 ° C. As the material of the nozzle, it is possible to use a corrosion-resistant metal such as stainless steel, Inconel, Hastelloy, quartz glass, or the like.

  The nozzle diameter of the gas introduction nozzle 47 is not particularly limited, but the standard nozzle diameter is usually equal to or less than the diameter of the substrate to be installed. Also, a shower head type nozzle having a plurality of source gas ejection holes on the nozzle end face is possible. When a shower head nozzle is used, the film thickness and film quality distribution of the obtained group III nitride become more uniform.

  Hereinafter, an operation procedure and various conditions for producing a group III nitride by the method of the present invention will be described by taking the case of using the apparatus shown in FIG. 4 as an example.

  In manufacturing group III nitride using the apparatus shown in FIG. 4, a substrate of the above-described material is placed on a susceptor. Next, a carrier gas other than the raw material is circulated, and the gas introduction nozzle 47 is heated to the temperature described above. The susceptor is then heated. Heating is performed at a heating temperature at which the reaction of the source gas proceeds and a group III nitride grows on the substrate, that is, in a range of 700 to 2000 ° C. After reaching a predetermined temperature, supply of a group III halide gas and a nitrogen source gas is started to deposit group III nitride on the substrate.

The supply amount of the raw material may be determined under the condition that solid precipitation does not occur with reference to FIG. 2, but the supply partial pressure of the group III halide gas is preferably 1 × 10 ⁻² atm or less, more preferably 1 × 10 ^-7 atm -1 × 10 ^-2 atm. If the supply partial pressure is larger than this, solid precipitation is likely to occur. The supply time of the raw material is a time for obtaining a desired film thickness. After stopping the supply of raw materials, the heating of the susceptor and the heating of the gas introduction nozzle are stopped, and after cooling, the substrate is taken out. The obtained group III nitride has been obtained through research conducted by the inventors of the present invention, which determines whether a single crystal or a polycrystal can be obtained depending on the growth temperature and growth rate. As a general tendency, the higher the growth temperature and the slower the growth rate, the easier it is to obtain a single crystal.

  The distance from the tip of the gas introduction nozzle to the center of the substrate affects the yield. The mixed gas of the group III halide gas and the nitrogen source gas discharged from the gas introduction nozzle reaches the substrate surface and reacts, and group III nitride is generated on the substrate surface. When the distance is long, the ratio of the source gas released from the gas introduction nozzle to be dissipated without reaching the substrate increases. For this reason, the raw material gas which reaches | attains the board | substrate surface reduces, and a yield falls. Furthermore, when the distance is long, the residence time until the mixed gas reaches the substrate becomes long, so that a solid group III nitride is generated in the gas phase, and a high-quality group III nitride film is obtained. It may not be possible. On the other hand, if the distance from the tip of the gas introduction nozzle to the center position of the substrate surface is too short, the high temperature substrate and the low temperature nozzle will be close to each other, making it difficult to control the respective temperatures. For this reason, the distance may be set in the range of 1 to 50 mm, more preferably 2 to 30 mm.

  Although the embodiment for carrying out the manufacturing method of the present invention using the apparatus shown in FIG. 4 has been described in detail, the apparatus used in the method of the present invention is not limited to that shown in FIG. The apparatus shown in FIG. 4 is an example of a vertical reactor, but it is also possible to use other types of vertical reactors, horizontal reactors, or reactors having both vertical and horizontal shapes. Moreover, reaction conditions etc. are suitably changed according to the apparatus to be used.

  According to the production method of the present invention, the group III nitride can be produced at a high speed and with a high yield. In addition, the crystallinity of the group III nitride obtained by appropriately selecting the manufacturing conditions can be controlled, and a single crystal substrate or a polycrystalline substrate can be easily manufactured.

  Therefore, the method of the present invention is suitable as a method for producing an aluminum nitride single crystal substrate or an aluminum gallium nitride single crystal substrate suitable as a substrate for producing an aluminum-based group III nitride semiconductor light emitting device. In particular, a mixed crystal composed of aluminum nitride and gallium nitride and / or indium nitride and having an aluminum nitride content of 20 mol% or more is also used as the substrate depending on the emission wavelength of the ultraviolet light emitting element. A mixed crystal single crystal substrate having such a composition changed can also be efficiently manufactured by the method of the present invention.

  If the group III nitride obtained in the present invention is a single crystal, it is peeled off from the substrate used for growth and the peeled surface is polished if necessary. What was polished with sufficient precision to the extent that atomic steps are generated by chemical mechanical polishing can be used as a substrate for a deep ultraviolet light emitting device as a self-supporting substrate.

  The yield, film formation rate of group III nitride, and crystallinity of the obtained group III nitride in the present invention can be evaluated by the following methods.

That is, the yield is the mass of the group III nitride crystal grown on the substrate from the change in mass of the substrate before and after growth, and this is the molecular weight of the group III nitride crystal (for example, in the case of aluminum nitride, the molecular weight is 41). To determine the number of gram atoms (A) of the group III metal immobilized on the substrate, and then the total number of gram atoms (B) of the group III halide supplied during the growth (of the mixed gas) (Supply flow rate / sccm) × (Group III halide gas supply partial pressure / atm) × (Supply time / min) ÷ (22400 / cc · mol ⁻¹ ), (A) divided by (B) It can be determined by converting it to a percentage.

The film formation rate can be determined by measuring the average film thickness of the obtained film and dividing the value by the film formation time. At this time, the average thickness of the obtained group III nitride crystal film is the mass of the grown crystal, the substrate area, and the density of the group III nitride crystal (for example, in the case of aluminum nitride, the density is 3.26 g / cm ³ It can be calculated from

  The crystal quality of the obtained crystal film can be evaluated by X-ray rocking curve measurement. The rocking curve is a diffraction obtained by fixing the detector at a position twice the angle at which a specific crystal plane satisfies the Bragg diffraction condition and changing the incident angle of the X-ray. The quality of the crystal quality can be judged from the half-value width. It can be said that the smaller the full width at half maximum, the better the crystal quality of the group III nitride crystal. The rocking curve measurement is usually performed in the (002) direction called Tilt (tilt). Further, an X-ray diffraction profile was measured in the range of 2θ of 10 to 100 ° by θ-2θ mode measurement. The θ-2θ mode measurement is a measurement method for measuring diffraction obtained by fixing a detector at a position of 2θ, where θ is an incident angle with respect to a sample. If only (002) diffraction and (004) diffraction are observed in the diffraction profile of the group III nitride crystal, it can be determined that the obtained group III nitride crystal is a single crystal. In the case of aluminum nitride, (002) diffraction is observed around 2θ = 36.039 °, and (004) diffraction is observed around 2θ = 76.439 °.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
A growth reaction of a single crystal of aluminum nitride, which is one of group III nitrides, was performed using the apparatus having the structure shown in FIG. Aluminum trichloride was used as the Group III metal-containing gas. The aluminum trichloride was generated and supplied by reacting hydrogen chloride with metal aluminum maintained at 500 ° C. upstream of the pipe 44 (not shown). Ammonia gas was used as the nitrogen source gas. The pipe 44, the pipe 45, the line mixer 50, and the gas mixer 46 were wound around a ribbon heater and heated to 300 ° C. The nozzle 47 is made of stainless steel (SUS316L) and has a structure (temperature control nozzle) that can circulate heat retaining oil inside the nozzle. The oil heated to 300 ° C. was circulated to keep the temperature of the nozzle at that temperature. At this time, the distance between the tip of the nozzle 47 and the surface of the substrate 43 was 25 mm. As a substrate, a sapphire c-plane substrate having a diameter of 2 inches was used, placed on the bottom surface of a boron nitride susceptor in which a carbon heating element was embedded, and the substrate temperature was heated to 1300 ° C. by supplying power to the carbon heating element. .

From the pipe 44, 4 sccm of aluminum trichloride gas was supplied after being diluted with 2996 sccm of hydrogen carrier gas, and 16 sccm of ammonia gas was supplied from the pipe 45 after being diluted with 4984 sccm of hydrogen carrier gas. The supplied gas merged in the mixer 46 via the pipe 44 and the pipe 45, and after being uniformly mixed by the line mixer, was supplied onto the substrate from the nozzle. Under these conditions, the supply partial pressure of aluminum trichloride in the mixed gas of 8000 sccm was 5 × 10 ⁻⁴ atm, and the molar ratio of ammonia gas to aluminum trichloride gas (V / III ratio) was 4. Further, nitrogen gas 3000 sccm was circulated around the nozzle as a purge gas for exhausting the system, but this purge gas is not directly related to the reaction. During the growth, the pressure in the system was maintained at 550 Torr (1 atmosphere is 760 Torr) by a dry pump having a pressure controller.

  The mixed gas was supplied to the substrate for 60 minutes to grow an aluminum nitride single crystal on the substrate. After 60 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling the substrate temperature to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the change in weight due to aluminum nitride grown on the substrate was plus 0.1057 g compared to before growth, the average film thickness of aluminum nitride was 16 μm, and the crystal growth rate was 16 μm / hr when converted to the deposition rate. . The amount of Group III metal immobilized on the substrate (the amount of immobilized Group III metal) was 0.0026 mol. Since the substance amount of the group III metal-containing gas supplied to the substrate during the growth (substrate supply group III metal substance amount) was 0.0107 mol, the yield was calculated to be 24%. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. Further, the rocking curve value of Tilt was 300 min.

Example 2
The same operation as in Example 1 was performed except that the substrate heating temperature was changed to 1600 ° C. in Example 1.

  A raw material mixed gas was supplied to the substrate for 60 minutes to grow an aluminum nitride single crystal on the substrate. After 60 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to the aluminum nitride grown on the substrate was 0.0925 g plus that before the growth, the average film thickness of the aluminum nitride was 14 μm, and the crystal growth rate was 14 μm / hr when converted to the deposition rate. . The amount of Group III metal immobilized on the substrate (the amount of immobilized Group III metal) was 0.0023 mol. Since the substance amount of the group III metal-containing gas supplied to the substrate during growth (substrate supply group III metal substance amount) was 0.0107 mol, the yield was calculated to be 21%. It was possible to grow aluminum group III nitride crystals stably even when the substrate was heated to a high temperature. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. Further, the rocking curve value of Tilt was 280 min.

Example 3
The apparatus having the structure shown in FIG. 4 was used, but the distance between the nozzle 47 and the surface of the substrate 43 in FIG. 4 was 10 mm, the substrate heating temperature was 1300 ° C., and the temperature control nozzle temperature was 200 ° C. Except for the above, the same operation as in Example 1 was performed.

  A raw material mixed gas was supplied to the substrate for 180 minutes to grow aluminum nitride crystals on the substrate. After 180 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to the aluminum nitride grown on the substrate was 0.6870 g plus that before the growth, the average film thickness of the aluminum nitride was 104 μm, and the crystal growth rate was 35 μm / hr when converted to the deposition rate. . The amount of Group III metal immobilized on the substrate (an amount of immobilized Group III metal) was 0.0168 mol. Since the amount of group III metal-containing gas supplied to the substrate during growth (substrate supply group III metal amount) was 0.0322 mol, the yield was calculated to be 52%. Since the distance between the nozzle and the substrate was short, the amount of raw material supplied reaching the substrate was thought to have increased, and the resulting aluminum nitride was white in appearance. From the θ-2θ mode X-ray diffraction profile, in addition to the (002) and (004) diffractions of aluminum nitride other than the sapphire substrate used for the substrate, (100) diffraction (2θ = 33.21 °), (101) Diffraction (2θ = 37.92 °), (102) Diffraction (2θ = 49.81 °), (103) Diffraction (2θ = 66.05 °), (200) Diffraction (2θ = 69.73 °), (202) Diffraction (2θ = 81.08 ° ) Was observed, and the obtained aluminum nitride was judged to be polycrystalline. The formation of polycrystals is thought to be due to the fact that the growth rate was high with respect to the substrate temperature.

Example 4
In Example 1, the same operation as in Example 1 was performed except that the distance between the nozzle 47 and the surface of the substrate 43 in FIG.

  A raw material mixed gas was supplied to the substrate for 60 minutes to grow aluminum nitride crystals on the substrate. After 60 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to the aluminum nitride grown on the substrate was 0.0727 g plus that before the growth, the average film thickness of the aluminum nitride was 11 μm, and the crystal growth rate was 11 μm / hr when converted to the deposition rate. . The amount of Group III metal immobilized on the substrate (an amount of immobilized Group III metal) was 0.0018 mol. Since the amount of group III metal-containing gas supplied to the substrate during growth (substrate supply group III metal amount) was 0.0107 mol, the yield was calculated to be 17%. The distance between the nozzle and the substrate was increased, so the amount of raw material supplied to the substrate decreased, and the yield was thought to have decreased. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. Further, the rocking curve value of Tilt was 270 min.

Example 5
The apparatus having the structure shown in FIG. 4 was used, but at the tip of the nozzle 47 in FIG. 4, a nozzle of a shower head type having a number of fine source gas ejection holes on the nozzle end surface was installed, and the tip of the nozzle and the substrate The same operation as in Example 1 was performed except that the distance from the surface of 43 was 10 mm and the substrate temperature was 1500 ° C. The diameter of the outermost periphery of the nozzle outlet by the shower head of the nozzle 47 was 50 mm, and 80 nozzle holes with a fine mixed gas having a diameter of 1 mm were arranged uniformly on the nozzle end face.

  A raw material mixed gas was supplied to the substrate for 60 minutes to grow aluminum nitride crystals on the substrate. After 60 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to aluminum nitride grown on the substrate was 0.2642 g compared to before growth, the average film thickness of aluminum nitride was 40 μm, and the crystal growth rate was 40 μm / hr when converted to the film formation rate. . Further, the amount of Group III metal immobilized on the substrate (the amount of immobilized Group III metal) was 0.0064 mol. Since the substance amount of the group III metal-containing gas supplied to the substrate during the growth (substrate supply group III metal substance amount) was 0.0107 mol, the yield was calculated to be 60%. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. Further, the rocking curve value of Tilt was 320 min.

Example 6
Using the apparatus having the structure shown in FIG. 4, aluminum gallium nitride was grown using a mixed gas of aluminum trichloride gas and gallium chloride gas as a group III halide gas. From the pipe 44, 0.15 sccm of aluminum trichloride gas and 0.1 sccm of gallium chloride gas were supplied after being diluted with a nitrogen carrier gas of 10,000 sccm, and 5 sccm of ammonia gas was supplied from the pipe 45 after being diluted with 4995 sccm of a nitrogen carrier gas. The supplied gases were combined in the mixer 46 and then supplied onto the substrate 43 from the temperature control nozzle 47 whose temperature was controlled at 300 ° C. Under these conditions, the supply partial pressure of aluminum trichloride gas in the mixed gas is 1 × 10 ⁻⁵ atm, the supply partial pressure of gallium chloride gas is 2 × 10 ⁻⁴ atm, and the ratio of ammonia gas to Group III metal-containing gas is 20 Met. Further, the same operation as in Example 1 was performed except that the substrate heating temperature was 1200 ° C. and the system internal pressure was 200 Torr.

  A raw material mixed gas was supplied to the substrate for 60 minutes to grow an aluminum gallium nitride crystal on the substrate. After 60 minutes, the supply of only the group III metal-containing gas was stopped to stop the growth of aluminum gallium nitride. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation.

  The change in weight due to aluminum gallium nitride grown on the substrate increased by 0.005 g compared to before growth. When the substrate was cut and the cross section was observed using a scanning electron microscope, the film thickness of aluminum gallium nitride was 0.58 μm, and the crystal growth rate was 0.58 μm / hr in terms of film formation rate. As a result of measuring the energy dispersive X-ray spectrum of the grown film, the aluminum: gallium element ratio in the aluminum gallium nitride was 70:30. As a result of calculating the molecular weight of aluminum gallium nitride from the ratio of the group III metal element to 53.9, the amount of the group III metal immobilized on the substrate (the amount of the group III metal immobilized) was 0.00093 mol. . Since the amount of group III metal-containing gas supplied to the substrate during growth (substrate supply group III metal amount) is 0.00041 mol, the yield is 23%. It was possible to grow aluminum gallium nitride crystals stably even when the substrate was heated to a high temperature. From the θ-2θ mode X-ray diffraction profile, only (002) and (004) diffractions of aluminum gallium nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum gallium nitride was a single crystal. Was confirmed.

Comparative Example 1
The growth reaction of aluminum nitride was performed using the apparatus having the structure shown in FIG. A conventional quartz glass triple tube nozzle was used as the nozzle. Aluminum trichloride was supplied from the central nozzle 15 as a Group III metal-containing gas, and nitrogen gas was circulated from the outer nozzle 16 as a barrier gas. Further, ammonia gas as a nitrogen source gas was supplied from the periphery of the nozzle 16 after being diluted with a hydrogen carrier gas. The distance from the nozzle 16 to the substrate surface was 50 mm as in Example 4. In addition, the substrate heating temperature, the piping heating temperature, the substrate heating temperature, the pressure, and the like were the same as in Example 1.

As supply conditions for the source gas, the aluminum trichloride gas of 4 sccm was diluted from the nozzle 15 with hydrogen gas of 4996 sccm as the carrier gas. From the barrier nozzle 16, 3000 sccm of nitrogen gas was supplied as a barrier gas. From the outer periphery of the nozzle, 16 sccm of ammonia gas was diluted with 3984 sccm of hydrogen gas as a carrier gas and supplied. At this time, the flow rate of the mixed gas was 12000 sccm in total, and the supply partial pressure of aluminum trichloride was 3.3 × 10 ⁻⁴ atm.

  A raw material mixed gas was supplied to the substrate for 60 minutes to grow an aluminum nitride single crystal on the substrate. After 60 minutes, the supply of only aluminum trichloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to the aluminum nitride grown on the substrate was 0.0350 g plus that before the growth, the average film thickness of aluminum nitride was 5.3 μm, and the crystal growth rate was 5.3 μm / hr when converted to the film formation rate. there were. Further, the amount of Group III metal immobilized on the substrate (the amount of immobilized Group III metal) was 0.00085 mol. Since the substance amount of the group III metal-containing gas supplied to the substrate during the growth (substrate supply group III metal substance amount) was 0.0107 mol, the yield was calculated to be 8%. Although the raw material supply amount is the same as that in Example 1, it is clear that the yield is lowered in this comparative example, and it can be said that the yield is higher in the premixed supply method of the present invention. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. The rocking curve value of Tilt was 220 min.

Comparative Example 2
In the apparatus of Example 1, it carried out like Example 1 except having used the nozzle made from quartz glass which cannot control temperature as a nozzle.

  Immediately after starting the supply of raw materials, white solid precipitates were observed near the tip of the quartz glass nozzle and on the inner wall, and accumulated over time.

  After the elapse of 60 minutes, the supply of only the III aluminum chloride gas was stopped and the growth of aluminum nitride was stopped. After cooling to 500 ° C., the ammonia gas was stopped, and after further cooling to room temperature, the substrate was taken out for evaluation. As a result, the weight change due to aluminum nitride grown on the substrate is 0.0086 g plus that before growth, the average film thickness of aluminum nitride is 1.3 μm, and the crystal growth rate is 1.3 μm / hr in terms of film formation rate. there were. The amount of Group III metal immobilized on the substrate (the amount of immobilized Group III metal) was 0.00021 mol. Since the amount of group III metal-containing gas supplied to the substrate during growth (substrate supply group III metal amount) was 0.0107 mol, the yield was calculated to be 2%. From the θ-2θ mode X-ray diffraction profile, only (002) diffraction and (004) diffraction of aluminum nitride were observed in addition to the sapphire substrate used for the substrate, and the obtained aluminum nitride was judged to be a single crystal. It was. Further, the rocking curve value of Tilt was 200 min.

  The white precipitated solid adhering to the quartz glass nozzle was found to be aluminum nitride from the powder X-ray diffraction measurement results. The reason for the significant decrease in the yield was that the temperature of the quartz glass nozzle rose due to the radiant heat from the heater for substrate heating, and the source gas was deposited as aluminum nitride on the tip and inner wall of the quartz glass nozzle before being supplied to the substrate caused by. Although the temperature of the nozzle during the reaction could not be measured, it is estimated that the temperature reached 600 ° C. or higher in consideration of the formation of aluminum nitride. That is, in the premixing supply system according to the present invention, it is shown that not only the gas temperature control during premixing but also the management of the nozzle temperature is important.

Comparative Example 3
In Example 1, it carried out similarly to Example 1 except having made the heating temperature of the oil circulated through the temperature control nozzle 100 ° C.

  White solid deposits were observed on the inner wall of the temperature control nozzle 47 immediately after starting the supply of the raw material, and the inner wall of the temperature control nozzle 47 was gradually blocked, so the experiment was stopped. That is, in the raw material supply system according to the present invention, it has been shown that stable growth is difficult unless the gas temperature during premixing is appropriately controlled.

  Table 1 shows the conditions and results of Examples and Comparative Examples.

This figure is a schematic view of a conventional vapor phase growth apparatus. It is a schematic diagram of the apparatus used in the reference experiment. It is the graph which put together the result of the reference experiment. 1 is a schematic view of a representative apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Growth chamber 12 External heating device 13 Susceptor having a heater function 14 Substrate 15 Group III halide gas nozzle 16 Barrier gas nozzle 17 Nitrogen source gas nozzle 21 Reaction tube (outer wall)
22 Group III halide introduction gas nozzle 23 Barrier gas nozzle 24 External heating device 41 Growth chamber 42 Susceptor with heater function 43 Substrate 44 Piping (for group III halide gas supply)
45 Piping (Nitrogen source gas supply)
46 Gas mixer 47 Temperature control nozzle 48 Gas inlet 49 Gas outlet 50 Line mixer

Claims (10)

In the method for producing a group III nitride comprising a growth step of causing a group III halide gas and a nitrogen source gas to react in a growth chamber and growing a group III nitride on a substrate held in the growth chamber, A premixing step of premixing the group halide gas and the nitrogen source gas before introducing them into the growth chamber, and the mixed gas obtained in the premixing step substantially contains precipitates in the gas. A method for producing a group III nitride, characterized in that it is introduced into the growth chamber without being formed into a growth chamber. The group III halide gas according to claim 1, wherein the group III halide gas is an aluminum halide gas or a mixed gas of an aluminum halide gas and a halide gas of a group III element other than aluminum. A method for producing nitride. The method of introducing the mixed gas obtained in the premixing step into the growth chamber without substantially generating precipitates in the gas is a method of mixing the group III halide gas and the nitrogen source gas in the premixing step. When the supply partial pressure of the group III halide gas to be supplied is P (atm), the temperature T (° C.) is

And a method of introducing the obtained mixed gas into the growth chamber at a temperature not lower than the lower limit temperature specified by the above formula (1) and lower than 600 ° C. The method for producing a group III nitride according to claim 1 or 2. The method for producing a group III nitride according to any one of claims 1 to 3, wherein the group III nitride is grown in the growth step at a substrate temperature of 700 ° C to 2000 ° C. The method for producing a group III nitride according to any one of claims 1 to 4, wherein the group III nitride is aluminum nitride. The group III nitride is a mixed crystal composed of aluminum nitride and gallium nitride and / or indium nitride, and is a group III nitride having an aluminum nitride content of 20 mol% or more. Item 5. A method for producing a group III nitride according to any one of Items 1 to 4. Group III nitridation having a growth chamber having a gas inlet for introducing a group III halide gas and a nitrogen source gas, a gas outlet, a support for holding the substrate, and a heating means for heating the substrate An apparatus for manufacturing a product, further comprising a gas introduction nozzle and a gas mixer having a temperature control function, wherein the gas introduction nozzle is mounted downstream of the gas mixer, and the gas mixer Is connected to a group III halide gas inlet and a nitrogen source gas inlet upstream of the group III nitride production apparatus. 8. The group III nitride production apparatus according to claim 7, wherein the temperature adjusting function of the gas introduction nozzle is a system in which heat exchange is performed with a liquid heat medium. The group III nitride production apparatus according to claim 7 or 8, wherein the gas introduction nozzle has a plurality of gas ejection holes. The group III nitride according to any one of claims 7 to 9, wherein the gas introduction nozzle is installed so that a distance from a tip of the gas introduction nozzle to a center of the substrate surface is 1 mm or more and 50 mm or less. Manufacturing equipment.

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