Metal trihalide gas manufacturing method and semiconductor material gas manufacturing apparatus

Abstract

To provide a method for producing a metal trihalide gas with excellent selectivity of a metal trihalide gas and excellent reactivity of a hydrogen halide and a metal, and a semiconductor material gas production device.SOLUTION: A method for producing a metal trihalide gas has a first step for reacting a metal with a hydrogen halide gas to produce a first gas containing a metal monohalide gas, and a second step for reacting the metal monohalide gas produced in the first step with a hydrogen halide gas to produce a second gas containing a metal trihalide gas.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a metal trihalide gas and an apparatus for producing a semiconductor material gas. [Background technology]

[0002] Wide bandgap semiconductors such as gallium nitride (GaN), aluminum nitride (AlN), and gallium(III) oxide (Ga2O3) are attracting attention as next-generation power device materials. Gallium arsenide (GaAs)-based semiconductors are also attracting attention as solar cell materials with higher performance than silicon (Si)-based semiconductors. One known method for forming these semiconductor crystal films is halide or hydride vapor phase epitaxy (HVPE), which is a method for forming semiconductor crystal films by reacting a metal halide with a Group V source such as ammonia or a Group VI source such as oxygen. In recent years, research into semiconductor film formation using the HVPE method has been actively conducted because of its fast growth rate of semiconductor crystals and its ability to produce high-purity films.

[0003] Patent Document 1 reports a method for producing a metal halide when a semiconductor film is formed using the metal halide, in which hydrogen chloride is used as a raw material gas and reacted with liquid metallic gallium to produce gallium monochloride.

[0004] Patent Document 2 describes a method for producing gallium trichloride by a two-step reaction using chlorine. In this method, gallium monochloride is produced by reacting chlorine and gallium at a high temperature with high efficiency in the first step, and gallium monochloride supplied from the first step is reacted with chlorine in the second step to produce gallium trichloride. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-43388 [Patent Document 2] Patent No. 5787324 Summary of the Invention [Problem to be solved by the invention]

[0006] The method for producing gallium monochloride described in Patent Document 1 has a problem in that gallium monochloride is decomposed into Ga and chlorine by the reaction shown in the following reaction formula, and precipitates as droplets. 2GaCl → 2Ga + Cl2 This issue is a "disproportionation reaction" phenomenon that becomes more pronounced at temperatures below 600°C, and depending on the raw material transport environment, it can cause problems with raw material supply. For example, if raw materials are supplied from an external source separately from the crystal film-forming section, it becomes difficult to maintain the raw material at a high temperature during transport, resulting in loss of raw material and blockages due to the precipitation of Ga droplets. For this reason, conventional HVPE equipment places the raw material generation section and film-forming section close to each other and configures them as a single furnace. However, because it makes it difficult to supply raw materials externally, which is considered advantageous for mass supply and control of the supply amount, this method is disadvantageous for mass production of semiconductor crystals and improved film thickness control. One possible solution to the above problem is to use hydrogen chloride as a source gas and react with gallium at low temperatures to produce gallium monochloride at high temperatures and gallium trichloride at low temperatures. This method utilizes the property that the reaction between hydrogen chloride and gallium preferentially produces gallium monochloride at high temperatures and gallium trichloride at low temperatures. This method allows the use of gallium trichloride, which is chemically stable and transportable, without the deposition of Ga droplets. However, this method requires the reaction temperature to be lowered to around 200°C to 300°C to selectively produce gallium trichloride, which reduces the reaction efficiency between gallium and hydrogen chloride. This reduction in reaction efficiency directly leads to a reduction in raw material utilization efficiency, which is disadvantageous in terms of cost and the mass supply of film-forming raw materials. Another common solution to the above problem is to vaporize solid gallium trichloride by heating. However, this method poses concerns about the purity of the raw material, as solid gallium trichloride is expensive and highly hygroscopic, making it suitable for semiconductor film formation, where even a small amount of impurities can affect conductivity control.

[0007] The method for producing gallium trichloride described in Patent Document 2 enables the production of gallium trichloride at high temperatures, thereby achieving both high reaction efficiency and selective production of gallium trichloride. In addition, the in-situ production of gallium trichloride using high-purity gas and high-purity gallium can be used without problems in semiconductor film formation processes that require high purity. On the other hand, this method is characterized by a two-step reaction using an inert gas such as nitrogen and chlorine, because the method of reacting gallium with hydrogen chloride is not suitable for mass production of gallium trichloride for the reasons mentioned above. However, since chlorine is a combustion-supporting gas, there is a problem that it is difficult to use in a reaction system using a flammable gas such as hydrogen due to concerns about explosive reactions from a safety standpoint. In general, semiconductor film deposition processes require the prevention of unintended impurities from being incorporated into the film. Hydrogen is often used as a carrier gas because its high reactivity allows it to react with impurities in the gas phase, such as carbon and oxygen, thereby preventing their incorporation into the film. In some cases, such as with GaAs, the use of hydrogen is expected to increase the growth rate during semiconductor film deposition and prevent the incorporation of nitrogen into the film. However, because hydrogen cannot be used as mentioned above, these film deposition processes do not utilize the two-step reaction using chlorine, but instead use a one-step reaction using hydrogen chloride to produce gallium monochloride or gallium trichloride, or vaporize solid gallium trichloride to supply the raw material together with hydrogen.

[0008] The two-step reaction using hydrogen halides has not been reported previously. This is because it is known that the reaction between gallium and hydrogen chloride is not suitable for mass production of gallium trichloride. Furthermore, even if the two-step hydrogen chloride reaction is carried out in the same way as with chlorine, it is not easy to selectively produce gallium trichloride. This is because the dechlorination reaction shown in the following reaction scheme predominates. GaCl3 + H2 → GaCl + 2HCl This dechlorination reaction is not limited to the use of hydrogen as a carrier gas; even when hydrogen is not used as a carrier gas, it proceeds due to the hydrogen generated after the reaction of hydrogen chloride with metal. In other words, this reaction means that when hydrogen is present in the system, most of the gallium monochloride supplied to the second stage flows out without becoming gallium trichloride. This tendency becomes more pronounced as the reaction temperature increases. In the two-stage reaction using chlorine, gallium trichloride remains stable even at high temperatures in the second stage, so both the first and second stages can be heated to high temperatures to increase reaction efficiency and suppress disproportionation reactions. However, in the two-stage reaction using hydrogen chloride, the high temperature in the second stage results in a higher proportion of gallium monochloride in the product.

[0009] In the two-stage reaction using hydrogen chloride, there are further challenges to overcome in solving the above problems. To achieve both the dechlorination of gallium trichloride with hydrogen, which is a factor in the difficulty of the two-stage reaction using hydrogen chloride, and the efficiency of raw material utilization, it is preferable to independently control the temperatures of the first and second stages, as described below. However, existing equipment intended for two-stage reactions using chlorine is not designed to independently control the first and second stages with a large temperature difference. To accurately control a certain temperature difference, for example, a temperature difference exceeding 100°C, in close proximity requires a drastic change in the mechanism. One possible solution would be to thermally shield the first and second stages, but this would make the mechanism more complex, making it difficult to ensure workability and airtightness. Also, because gallium monochloride is transported between the first and second stages, there is concern that Ga droplets may be generated if the temperature drops. It should be noted that all of the above-mentioned problems are merely examples, and there is a concern that problems similar to or close to the above-mentioned problems may occur when metals other than gallium, such as aluminum or indium, which are Group III metals like gallium, are used, and when not only hydrogen chloride but also hydrogen halides in general, which have similar chemical properties, such as hydrogen iodide and hydrogen bromide, are used.

[0010] An object of the present invention is to provide a method for producing a metal trihalide gas and a semiconductor material gas production apparatus which are excellent in selectivity for the metal trihalide gas and in reactivity between hydrogen halide and the metal. [Means for solving the problem]

[0011] [1] a first step of reacting a metal with a hydrogen halide to produce a first gas comprising a metal monohalide gas; and a second step of reacting the first gas with hydrogen halide to produce a second gas containing a metal trihalide gas; A method for producing a metal trihalide gas comprising: [2] The method for producing a metal trihalide gas according to [1], wherein the second gas further contains a metal monohalide gas, and the ratio of the metal monohalide gas to the metal trihalide gas in the second gas is 10 mol % or less. [3] The method for producing a metal trihalide gas according to [1] or [2], wherein the utilization efficiency of the hydrogen halide after the first step and the second step is 90% or more of the theoretical value. [4] The method for producing a metal trihalide gas according to any one of [1] to [3], wherein the metal is one or both of gallium and indium. [5] The method for producing a metal trihalide gas according to any one of [1] to [4], wherein hydrogen chloride is used as the hydrogen halide. [6] The method for producing a metal trihalide gas according to any one of [1] to [5], wherein the temperature at which the first step is carried out and the temperature at which the second step is carried out are optimum temperatures for each step. [7] The method for producing a metal trihalide gas according to any one of [1] to [6], wherein in the first step, the metal and the hydrogen halide are reacted at a temperature of 200° C. or higher. [8] The method for producing a metal trihalide gas according to any one of [1] to [7], wherein in the second step, the metal and the hydrogen halide are reacted at a temperature of 250°C to 700°C. [9] The method for producing a metal trihalide gas according to any one of [1] to [8], wherein at least one gas selected from the group consisting of nitrogen gas, argon gas, and helium gas is used as a carrier gas for the hydrogen halide.

[10] The method for producing a metal trihalide gas according to any one of [1] to [8], wherein a flammable gas or a mixed gas containing a flammable gas is used as a carrier gas for the hydrogen halide.

[11] The method for producing a metal trihalide gas according to

[10] , wherein the flammable gas is hydrogen gas.

[12] The method for producing a metal trihalide gas according to any one of [9] to

[11] , wherein the ratio of the hydrogen halide to the total number of moles of the hydrogen halide and the carrier gas is 10 mol % or more.

[13] The method for producing a metal trihalide gas according to any one of [1] to [8], wherein a carrier gas for the hydrogen halide is not used.

[14] one or more first stage reaction zones for reacting a feed gas with a solid or liquid feed to produce a first gas; one or more second stage reaction zones for reacting the first gas with a feed gas to produce a second gas; a raw material gas flow path for supplying a raw material gas to the first step reaction compartment and the second step reaction compartment; a first gas flow path for transporting the first gas from the first stage reaction compartment to the second stage reaction compartment; a gas flow path for discharging the second gas from the second step reaction compartment; a first heating mechanism for heating the first step reaction compartment; a second heating mechanism for heating the second step reaction compartment; Equipped with the first heating mechanism and the second heating mechanism are capable of independently controlling the temperatures of the first step reaction compartment and the second step reaction compartment, respectively; Semiconductor material gas manufacturing equipment.

[15] The semiconductor material gas manufacturing apparatus according to

[14] , which uses the method for manufacturing a metal trihalide gas according to any one of [1] to

[13] .

[16] The semiconductor material gas manufacturing apparatus according to

[14] or

[15] , wherein the first step reaction compartment and the second step reaction compartment are insulated from each other by a vacuum, a gas, or a heat insulating member.

[17] A rigid body is provided between the first step reaction compartment and the second step reaction compartment, the rigid body has a gas flow path for transporting the raw material gas between the first step reaction compartment and the second step reaction compartment; The interior of the rigid body is vacuum or filled with gas or a heat insulating material. The semiconductor material gas manufacturing apparatus according to any one of

[14] to

[16] .

[18] The first step reaction compartment and the second step reaction compartment have at least one first recess or first protrusion on their joint surfaces with the rigid body, The rigid body has at least one second protrusion or second depression B on its joint surface with the first step reaction compartment and the second step reaction compartment;

[17] A semiconductor material gas manufacturing apparatus according to

[17] , wherein when the rigid body is installed between the first process reaction compartment and the second process reaction compartment, the first recess and the second protrusion or the first protrusion and the second recess are fitted together, and the protruding lengths of the first protrusion and the second protrusion are equal to or less than the recessed lengths of the second recess and the first recess, respectively.

[19] A semiconductor material gas manufacturing apparatus according to any one of

[14] to

[18] , comprising one or more independently controllable heating mechanisms between the heating mechanism for the first process reaction compartment and the heating mechanism for the second process reaction compartment.

[20] The semiconductor material gas manufacturing apparatus according to any one of

[14] to

[19] , wherein the distance between the first step reaction compartment and the second step reaction compartment is 200 mm or less.

[21] A semiconductor material gas manufacturing apparatus described in any of

[14] to

[20] , wherein the first heating mechanism and the second heating mechanism maintain the inside or vicinity of the first process reaction compartment and the second process reaction compartment within a range of ±50°C of the target temperature, regardless of whether the first heating mechanism and the second heating mechanism set the first process reaction compartment and the second process reaction compartment to the same target temperature or whether the first process reaction compartment and the second process reaction compartment are set to different target temperatures.

[22] The semiconductor material gas manufacturing apparatus according to

[21] , wherein the different target temperatures are at least two different target temperatures selected from temperatures of 200°C or higher and 1000°C or lower, and the smallest temperature difference among the differences between the target temperatures is 50°C or higher.

[23] The semiconductor material gas manufacturing apparatus according to any one of

[14] to

[22] , wherein the material gas produced by reaction in the semiconductor material gas manufacturing apparatus is a source gas used to form a compound semiconductor crystal consisting of at least one element selected from the group consisting of B, Al, Ga, and In, and at least one element selected from the group consisting of N, As, P, and O, or a crystal obtained by doping the compound semiconductor crystal with an impurity.

[24] The semiconductor material gas manufacturing apparatus according to any one of

[14] to

[23] , further comprising a flow path for introducing a gas into the gas flow path downstream of the second step reaction zone. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a method for producing a metal trihalide gas and a semiconductor material gas reaction apparatus which are excellent in selectivity for the metal trihalide gas and in reactivity between hydrogen halide and metal. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a graph showing the temperature dependence of the partial pressure of each gas species when the carrier gas is hydrogen and the hydrogen chloride supply partial pressure is 2×10 −1 atm in the first step of the method for producing a metal trihalide gas of the present invention. [Figure 2]FIG. 2 is a graph showing the temperature dependence of the partial pressure of each gas species in the second step of the method for producing a metal trihalide gas of the present invention when the first step of FIG. 1 is performed at 850° C. [Figure 3] FIG. 3 is a graph showing the temperature dependence of the partial pressure of each gas species when the hydrogen chloride supply partial pressure is set to 1 atm in the first step of the method for producing a metal trihalide gas of the present invention. [Figure 4] FIG. 4 is a graph showing the temperature dependence of the partial pressure of each gas species in the second step of the method for producing a metal trihalide gas of the present invention when the first step of FIG. 3 is performed at 850° C. [Figure 5] FIG. 5 is a graph showing the temperature dependence of the partial pressure of each gas species in the second step of the method for producing a metal trihalide gas of the present invention when the first step of FIG. 3 is performed at 400° C. [Figure 6] FIG. 6 is a schematic diagram of an example of the semiconductor material gas manufacturing apparatus of the present invention. [Figure 7] FIG. 7 is a gas system diagram of an example of a semiconductor material gas manufacturing apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] In order to solve the above-mentioned problems, the present inventors conducted a study based on the results of thermodynamic analysis and focused on a two-step reaction mechanism using hydrogen halide. Specifically, the present invention has devised a method for producing metal trihalide gas, which includes a first step of reacting a metal with hydrogen halide to produce a first gas containing metal monohalide gas, and a second step of reacting the first gas produced in the first step with hydrogen halide to produce a second gas containing metal trihalide gas. This method allows for selective production of metal trihalide gas at high temperatures using hydrogen halide, something that has been difficult to achieve in the past, and an apparatus that enables this. The principles of the present method for producing metal trihalide gas were derived using thermodynamic analysis and are the result of research by the present inventors.

[0015] [Metal trihalide gas production method] Hereinafter, a method for producing gallium trichloride gas will be described as one embodiment of a method for producing metal trihalide gas. Figures 1 to 5 are graphs showing the temperature dependence of the equilibrium partial pressure of each gas species thought to be involved in the production of gallium trichloride gas, calculated using thermodynamic analysis. The total pressure in the reaction system is 1 atm. The gas partial pressures on the vertical axes of Figures 1 to 5 are on a logarithmic scale.

[0016] FIG. 1 is a graph showing the temperature dependence of the equilibrium partial pressure of each gas species in the first step when hydrogen gas is used as a carrier gas for hydrogen chloride gas. FIG. 2 is a graph showing the temperature dependence of the equilibrium partial pressure of each gas species in the second step when hydrogen gas is used as a carrier gas for hydrogen chloride gas. In Figure 1, the partial pressure of hydrogen chloride gas supply is 1 x 10 -1 In Figure 2, the partial pressures of gas species other than hydrogen chloride gas and hydrogen gas were calculated using formula (1), hydrogen chloride gas was calculated using formula (2), and hydrogen gas was calculated using formula (3), based on the partial pressures of each gas species in Figure 1 when the first step was performed at 850°C.

[0017]

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[0018]

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[0019]

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[0020] In formula (1), P f x and P o x are the partial pressures of gas species x immediately after the reaction in the first step and when supplied in the second step, respectively. In formula (3), ΣP o w / oH2is the total partial pressure of gas species other than hydrogen gas when supplied in the second step.

[0021] These conditions assume that the second step is carried out by diluting the first gas produced in the first step with enough hydrogen chloride gas, theoretically necessary to convert all of the gallium monochloride gas produced in the first step into gallium trichloride gas, with the carrier gas to achieve the same flow rate as the gas flowing out of the first step. Note that Figure 1, which shows the thermodynamic analysis results for the first step, can also be interpreted as the thermodynamic analysis results for a one-step reaction using hydrogen chloride gas.

[0022] As mentioned above, in semiconductor gas production, it is desirable to selectively generate metal trihalide gas due to advantages such as the large supply of raw materials. When the molar ratio of metal monohalide gas to metal trihalide gas is Rm, the lower Rm is, the better from the viewpoint of selective generation of metal trihalide gas. Specifically, Rm is preferably 10 mol% or less, more preferably 5 mol% or less, and even more preferably 1 mol% or less. Based on the above, Fig. 1 and Fig. 2 are compared. Fig. 1 shows that in order to selectively generate gallium trichloride gas by only the first step, i.e., a one-step reaction, the reaction temperature is preferably at most around 300 ° C., and in order to generate gallium trichloride gas at a lower Rm, it is preferable to set the reaction temperature at around 250 ° C. In contrast, Fig. 2 shows that by going through the second step, gallium trichloride can be selectively generated even at a higher reaction temperature than in the case of only the first step, specifically, at around 450 ° C.

[0023] 3, 4, and 5 are graphs showing the temperature dependence of the equilibrium partial pressure of each gas species in the first and second steps when hydrogen chloride gas is supplied without using a carrier gas. In FIG. 3, which illustrates the first step, the supply partial pressure of hydrogen chloride gas is 1 atm. In FIGS. 4 and 5, which illustrate the second step, the results are obtained when partial pressures calculated using equations (1) to (3) in the same way as in FIG. 2 are supplied based on the partial pressures of each gas species when the first step (FIG. 3) is performed at 850°C and 400°C, respectively.

[0024] 2 and 4, it can be seen that the condition in which hydrogen chloride gas is supplied without using a carrier gas maintains a low Rm even at high temperatures in the second step, specifically at 600°C or higher. In other words, the higher the concentration of hydrogen chloride gas supplied, the more selectively gallium trichloride gas can be produced at higher temperatures. In particular, by supplying hydrogen chloride gas at a concentration of 100%, gallium trichloride gas can be produced at temperatures higher than those of the conventional one-step gallium trichloride gas reaction using hydrogen chloride gas, which is 600°C or higher. On the other hand, the concentration of hydrogen chloride gas in the second gas, which is the product of the second step, is at the same level as the concentration of gallium trichloride gas. Hereinafter, for convenience, the hydrogen chloride gas in the second gas, which is the product of the second step, will be referred to as "unreacted HCl," and the unreacted HCl ratio Rh, which is the value calculated by equation (4), will be used as an index representing the concentration of unreacted HCl.

[0025]

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[0026] Unreacted HCl remains and is supplied to the deposition furnace regardless of the reaction efficiency, which increases with increasing reaction temperature. A certain amount of hydrogen chloride gas supplied to the deposition furnace is thought to suppress powder formation in the gas layer and is not particularly problematic. However, if you want to reduce the residual hydrogen chloride gas for reasons such as improving raw material utilization efficiency or because it can cause etching during deposition, even if you simply increase the reaction temperature to increase reaction efficiency and reduce the residual hydrogen chloride gas concentration, especially under conditions where the supplied hydrogen chloride gas concentration is high, there is a possibility that the increase in Rh will actually increase the residual hydrogen chloride gas concentration.

[0027] Assuming that Rh content is to be reduced further than that shown in Figure 4, the thermodynamic analysis results based on the specified conditions are shown in Figure 5. Figure 5 shows the results when the temperature of the first step is deliberately lower than the 850 °C shown in Figure 4, specifically, when the second step is performed under the partial pressure condition of 400 °C shown in Figure 3. This indicates that Rh content is reduced overall. This indicates that lowering the reaction temperature in the first step to a level that does not reduce reaction efficiency reduces the concentration of gallium monochloride gas generated in the first step, which in turn reduces the amount of hydrogen chloride gas required to convert gallium monochloride gas to gallium trichloride gas, thereby significantly reducing Rh content. Therefore, it is possible to selectively generate gallium trihalide gas according to various film formation conditions, taking into account the concentration of each product gas species.

[0028] As described above, the present invention provides a method for producing metal trihalide gas that enables flexible and efficient selective production of metal trihalide gas by independently setting the temperatures of the first and second steps in accordance with the various circumstances of each operator of the present invention while focusing on the allowable value of Rh.

[0029] 1 to 5 and the conditions described based on them are merely defined for the purpose of explaining the principles of the present invention, and are not necessarily conditions that should be used in the present invention. The point to note in the above explanation is that by going through the second step, it is possible to selectively generate metal trihalide gas at a higher temperature than when metal trihalide gas is selectively generated only through the first step.

[0030] In light of the above, specific explanations of means for solving the above problems will be given below. The method for producing a metal trihalide gas of the present invention includes a first step of reacting a metal with a hydrogen halide gas to produce a first gas containing a metal monohalide gas, and a second step of reacting the first gas produced in the first step with a hydrogen halide gas to produce a second gas containing a metal trihalide gas.

[0031] The metal used in the method for producing a metal trihalide gas of the present invention is, for example, a Group III metal (a Group 13 metal element) such as aluminum, gallium, indium, or thallium. Among these, one or both of gallium and indium are preferred, and gallium is more preferred.

[0032] The hydrogen halide gas used in the method for producing a metal trihalide gas of the present invention is, for example, hydrogen chloride gas, hydrogen bromide gas, or hydrogen iodide gas, with hydrogen chloride gas being preferred among these.

[0033] In the first step of the method for producing a metal trihalide gas of the present invention, the temperature (first step reaction temperature) at which the metal reacts with hydrogen halide gas is preferably 200°C or higher. Because the reaction efficiency between the metal and hydrogen halide gas improves with increasing temperature, the first step reaction temperature is more preferably 300°C or higher, and even more preferably 400°C or higher. However, when aiming to suppress the unreacted HCl ratio Rh in the second step, it is effective to perform the reaction between the metal and hydrogen halide gas in the first step at a relatively low temperature to reduce the metal monohalide gas concentration in the first gas produced in the first step. In this case, the first step reaction temperature is preferably 700°C or lower, more preferably 600°C or lower. Therefore, when it is desired to reduce the residual hydrogen halide gas concentration in the second gas, which is the final product, it is preferable to optimize the temperature conditions, for example, by setting the first step reaction temperature within the range of 400 to 600°C, and exploring conditions that maximize raw material utilization efficiency while taking into account the balance between improving reaction efficiency through high-temperature reaction and suppressing Rh through low-temperature reaction.

[0034] In the second step of the method for producing a metal trihalide gas of the present invention, the temperature at which the first gas and hydrogen halide gas are reacted (second-step reaction temperature) is preferably as high as possible from the viewpoint of reaction efficiency, and is preferably 250°C or higher, more preferably 300°C or higher, and even more preferably 400°C or higher. A second-step reaction temperature of 250°C or higher is advantageous over metal trihalide gas production by a single-step reaction, and is preferably 300°C or higher, more preferably 350°C or higher, and even more preferably 400°C or higher. On the other hand, the thermodynamic analysis results show that the molar ratio Rm of metal monohalide gas to metal trihalide gas tends to increase as the second-step reaction temperature is increased. Therefore, to improve the selectivity of metal trihalide gas production, the second-step reaction temperature is preferably 700°C or lower, more preferably 600°C or lower, and even more preferably 550°C or lower. In view of the above, it is preferable to adjust the second step reaction temperature, for example, within a range of 350 to 600°C, by considering the balance between the residual amount of hydrogen halide gas and the ideal Rm value described above depending on the purpose of semiconductor material gas generation, and to seek optimal conditions.

[0035] The method for producing a metal trihalide gas of the present invention uses, as a raw material, hydrogen halide, which is a non-combustible gas, rather than a combustion-sustaining gas such as chlorine, and therefore can be used in a system in which a flammable gas such as hydrogen gas is present without concern for an explosive reaction between the flammable gas and the combustion-sustaining gas. Therefore, the method for producing a metal trihalide gas of the present invention can use a flammable gas such as hydrogen gas as a carrier gas, in the same way as non-flammable gases such as nitrogen gas, argon gas, and helium gas.

[0036] The hydrogen halide gas supplied in the method for producing metal trihalide gas of the present invention is generally diluted with a carrier gas before supply, as is the case with other semiconductor material gases. However, according to the thermodynamic analysis results described above, the higher the concentration of hydrogen halide gas, the lower the Rm can be maintained even at higher temperatures. Therefore, by supplying a hydrogen halide gas concentration of 10 mol% or more relative to the total number of moles of hydrogen halide gas and carrier gas, it is possible to efficiently and selectively produce metal trihalide gas at higher temperatures. Furthermore, by using liquefied hydrogen halide and supplying hydrogen halide at a concentration of 100% without diluting it with a carrier gas, it is possible to selectively produce metal trihalide at even higher temperatures.

[0037] Specific embodiments for carrying out the method for producing a metal trihalide gas of the present invention are shown below, but the present invention is not limited to the embodiments shown below. The present invention is an extremely flexible invention that can be applied to a wide variety of reaction conditions according to the level of requirements at any given time, with modifications to the detailed specifications in some cases, and therefore the embodiment of the method for producing a metal trihalide gas of the present invention shown below is merely an example.

[0038] Table 1 shows the product ratios for gallium trichloride production derived by thermodynamic analysis under conditions based on a conventional method, and Table 2 shows the product ratios for conditions incorporating the second step of the present invention. It is known that values calculated using thermodynamic analysis accurately reproduce the temperature dependence of partial pressure in actual reactions, and it is expected that the calculated values shown here will also show a similar trend to the actual results. The GaCl3 / GaClx ratio in Tables 1 and 2 is calculated using Equation (5). The maximum raw material utilization efficiency in Tables 1 and 2 is the theoretical maximum raw material utilization efficiency when the reaction efficiency is 100% and only unreacted HCl remains, and is calculated using Equation (6). The conditions listed in Table 2 were selected to achieve a GaCl3 / GaClx ratio of approximately 99%, assuming operation in an external gallium trichloride production system, as described below.

[0039]

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[0040]

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[0041] When hydrogen chloride was used as the Cl source gas, the results of the second step in Table 2 all showed that gallium trichloride could be produced at a higher temperature with the same selectivity as when only the first step in Table 1 was used. For example, when a hydrogen carrier was used and the hydrogen chloride supply partial pressure was 2 × 10 -1 At atmospheric pressure, selective production of gallium trichloride is possible at high temperatures of 400°C in the first step and 310°C in the second step. Furthermore, selective production of gallium trichloride is possible even at high temperatures of 700°C in the first step and 400°C in the second step, although the maximum raw material utilization efficiency is slightly reduced.

[0042] In Table 2, when only hydrogen chloride gas is supplied as the feed gas and the first step is performed at 400°C and the second step at 380°C, high-temperature production, high selectivity for gallium trichloride, and high maximum feedstock utilization efficiency are both achieved. In addition, if a decrease in feedstock utilization efficiency is acceptable, conditions in which only hydrogen chloride gas is supplied as the feed gas and the first step is performed at 700°C and the second step at 540°C are also preferable.

[0043] [Table 1]

[0044] [Table 2]

[0045] [Semiconductor material gas manufacturing equipment] 6 includes one or more first-step reaction zones S1 for reacting a source gas G0 with a solid or liquid source M1 to produce a first gas G1, one or more second-step reaction zones S2 for reacting the first gas G1 with the source gas G0 to produce a second gas G2, a source gas flow path L0 for supplying the source gas G0 to the first-step reaction zone S1 and the second-step reaction zone S2, a first gas flow path L1 for transporting the first gas G1 from the first-step reaction zone S1 to the second-step reaction zone S2, a gas flow path L2 for discharging the second gas G2 from the second-step reaction zone, a first heating mechanism H1 for heating the first-step reaction zone S1, and a second heating mechanism H2 for heating the second-step reaction zone S2. Hereinafter, the first and second heating mechanisms may be collectively referred to as "heating mechanisms." The first heating mechanism H1 and the second heating mechanism H2 can independently control the temperature of each of the first adjacent reaction compartment and the second adjacent reaction compartment, which are one or more pairs of two adjacent reaction compartments among the first process reaction compartment S1 and the second process reaction compartment S2.

[0046] The semiconductor material gas manufacturing apparatus of the present invention is suitably used for operating a semiconductor material gas reaction process involving heating, particularly a semiconductor material gas reaction process in which the reaction step is divided into two or more stages and the reaction is carried out at different temperatures, and is suitably used, for example, as an apparatus for operating the semiconductor material gas reaction method of the present invention.

[0047] In addition to the heating mechanism, a thermal insulation mechanism can be provided, providing a space or a thermally insulating material between two or more reaction compartments with a temperature difference, thereby improving temperature controllability. By making this thermal insulation mechanism a rigid body, it is possible to have it function as a member supporting the reaction compartments and, by installing piping inside, as a gas transport channel between the reaction compartments. In this case, it is necessary to align the gas channels between the reaction compartments and the thermally insulating rigid body. To simplify the alignment process, it is preferable to provide protrusions and recesses on the mating surfaces of each component so that they can be fitted together. Using two or more protrusions and recesses can prevent misalignment in the rotational direction. Furthermore, to suppress gas leakage from the gap between the reaction compartments and the thermally insulating rigid body, it is preferable that the depth of the recesses is greater than the height of the protrusions. The gas channels within the rigid body are preferably located close to the heating mechanism in consideration of temperature controllability, but they may also be located inside the rigid body in consideration of heat retention in situations such as when the temperature difference between the reaction compartments is small.

[0048] Furthermore, by providing an independent temperature-controllable third heating mechanism for heating the vicinity of the heat insulating mechanism in addition to the heating mechanism for heating the reaction compartment, it becomes possible to control a steeper temperature gradient.

[0049] Generally, if heating sections with different set temperatures are not spaced far enough apart, the greater the difference in set temperatures, the greater the deviation from the target temperature due to the influence of the temperatures of the heating sections before and after. However, in the semiconductor material gas manufacturing apparatus of the present invention, the reaction sections whose temperatures can be independently controlled can be sufficiently controlled independently even if they are relatively close to each other. Specifically, the reaction sections whose temperatures can be independently controlled can be operated with a distance of 200 mm or less.

[0050] The heating mechanism in the semiconductor material gas manufacturing apparatus of the present invention has a controllable temperature difference range with a lower limit of 0°C and an upper limit of preferably 50°C or higher, more preferably 100°C or higher, based on the results of thermodynamic analysis. From the viewpoint of improving the degree of freedom in reaction conditions, temperatures above 100°C, for example, 200°C or higher, are even more preferred. Furthermore, it is preferable that the actual temperature near or inside the reaction compartment does not deviate significantly from the set value due to fluctuations in the settable temperature difference. The smaller this deviation temperature is, the better. Specifically, when the temperature is stable, it is preferably ±50°C or less from the set value, more preferably ±20°C or less, and even more preferably ±10°C or less.

[0051] The semiconductor material gas manufacturing apparatus of the present invention is suitably used for supplying raw materials for film formation of semiconductor crystals such as GaN and Ga2O3. 1-x-y Ga x In y N-series and (Al 1-x-y Ga x In y It is also suitable for use in supplying raw materials for film formation of semiconductor alloy crystals such as Al. 1-x-y Ga x In y It is suitable for use in supplying raw materials for film formation of crystals, such as As-based crystals, which are generally grown using hydrogen carriers.

[0052] Hydrogen gas, which is preferred as a carrier gas in the present invention, promotes the dechlorination reaction of metal trihalide gas at high temperatures. Therefore, if the hydrogen chloride concentration in the product is to be reduced, a low hydrogen concentration in the reaction zone is preferable. Even when a carrier gas other than hydrogen gas is used, a high halide source concentration allows for selective generation of metal trihalide gas at higher temperatures. Therefore, a low carrier gas concentration is generally advantageous for selective generation of metal trihalide gas. On the other hand, if the metal trihalide gas is not sufficiently diluted by the carrier gas, the partial pressure of the metal trihalide gas increases. If the transport route to the crystal film formation zone is at a lower temperature than the reaction zone, the metal trihalide may easily precipitate in the piping. Therefore, by providing a mechanism for transporting metal trihalide gas using only hydrogen halide gas or hydrogen halide gas diluted with a small amount of hydrogen, and then adding hydrogen gas in the low-temperature zone after generation, at a temperature above the boiling point of gallium trihalide and at least below the reaction temperature of the second step, the intended source concentration can be maintained by suppressing the dechlorination reaction while suppressing gallium trihalide crystal precipitation in the piping.

[0053] Specific embodiments for implementing the semiconductor material gas manufacturing apparatus of the present invention are shown below, but are not limited to the following embodiments. The present invention is an extremely flexible invention that can be applied to a wide variety of reaction conditions according to the level of demand at any given time, even while changing the detailed specifications in some cases, and therefore the embodiment of the semiconductor material gas manufacturing apparatus of the present invention shown below is merely an example.

[0054] By incorporating the mechanism of the semiconductor material gas production apparatus of the present invention as part of a film formation furnace using the HVPE method, it is possible to operate it safely even under film formation conditions using hydrogen as a carrier gas. Furthermore, by installing it as a device separate from the film formation furnace as a device for supplying film formation raw materials from outside to a growth furnace using the HVPE method, it becomes easier to supply raw materials in larger quantities than with the above method, and an improvement in film formation rate can be expected. Below, we will explain an example where the purpose is to supply gallium trichloride generated by supplying hydrogen chloride with a hydrogen carrier from outside the film formation furnace.

[0055] 6 shows a schematic longitudinal cross-sectional view of a gallium trichloride gas production apparatus (semiconductor material gas production apparatus 100) for supplying gallium trichloride from outside a film formation furnace. This apparatus includes a storage container C1, such as a cylindrical quartz tube, covered with heating mechanisms H1 and H2, such as a mantle heater. The storage container C1 contains two carbon first-step reaction compartments S1 (S11, S12) for reacting hydrogen chloride gas (source gas G0) with liquid gallium (solid or liquid source M1), one carbon second-step reaction compartment S2 for reacting the first gas G1 generated in the first-step reaction compartment S1 with the hydrogen chloride gas G0, and a thermal insulating quartz member (thermal insulating member I1) sandwiched between the first-step reaction compartment S1 and the second-step reaction compartment S2. It also includes a gas flow path L0 for supplying hydrogen chloride gas (raw material gas G0) to the first step reaction section S1, a gas flow path L0' for supplying hydrogen chloride gas (raw material gas G0') to the second step reaction section S2, a gas flow path L1 for transporting the first gas G1 between the first step reaction section S1 and the second step reaction section S2, and a gas flow path L2 for discharging gas from the second step reaction section S2.

[0056] The gallium trichloride gas production apparatus can be made of any material that can withstand temperatures of 200°C or higher, such as quartz or metal, but it is more preferable that the first-step reaction section S1 and the second-step reaction section S2 be made of a material that is relatively resistant to corrosion by the raw material metals and halides. For example, in addition to carbon, materials such as BN (boron nitride), metals and quartz that have been treated with corrosion resistance, such as silica coating or PTFE / Ni (electroless nickel Teflon) coating, are preferred.

[0057] The mantle heater is installed to heat the interior through the quartz tube. Separate temperature control systems are installed around the first-step reaction compartment, the insulating quartz element, and the second-step reaction compartment. This allows for independent control of the first-step reaction compartment S1 and the second-step reaction compartment S2. Furthermore, by controlling the temperature of the insulating quartz element according to the temperatures of the upper and lower first-step reaction compartment S1 and second-step reaction compartment S2, rapid temperature control is possible even when the temperature difference between the first and second-step reaction compartments is large. Since it is difficult to adequately control the temperature at the end of the heater, the heaters around the reaction compartments are positioned with a margin, slightly overlapping the insulating quartz element, ensuring a constant temperature throughout the entire reaction compartment. Therefore, the heaters around the insulating quartz element are slightly smaller than the insulating quartz element.

[0058] The first-step reaction compartment S1 and the second-step reaction compartment S2 are cylindrical, with an outer shell approximately 20 mm thick. The gas flow path is integrated with the reaction compartments through holes drilled in the outer shell. The outer shell of the insulating quartz element also has a gas flow path connecting the gas flow paths of the upper and lower reaction compartments. This eliminates the need for complex piping to the reaction compartments, simplifying the device structure, reducing manufacturing costs, and improving operability. Additionally, providing a gas flow path in the outer shell of the insulating quartz element makes it easier to reflect the temperature control effects of the heater surrounding the insulating quartz element. While Figure 6 shows gas flow paths only on the left and right sides for convenience in illustrating the plan view, the gas flow paths can be located anywhere around the reaction compartments. A more simplified structure can be achieved by offsetting the gas flow paths from the same longitudinal cross section.

[0059] The insulating quartz member has a vacuum inside to enhance its insulating effect. Note that the insulating quartz member can be any rigid body that can insulate the upper and lower parts, and the same effect can be achieved by filling the inside of a hollow quartz member with insulating material, or by sandwiching insulating material between two quartz plates connected vertically by a pillar, etc. The reaction compartments are equipped with carbon lids on top, and each compartment can be separated for easy internal maintenance, such as raw material supply and cleaning. The reaction compartments have two recesses on the surface that contacts the insulating quartz member, and the insulating quartz member has two protrusions, each slightly smaller than the recesses, at corresponding positions. This allows for easy alignment of the gas flow paths during repairs. Furthermore, because the protrusions are deeper than the recesses, the contact surfaces between the reaction compartment and the insulating quartz member are tightly fitted, enabling gas transport with minimal leakage outside the flow path. Furthermore, by placing the recesses on the side of the carbon reaction compartment, which is made of a material that is easy to machine, the difficulty of fabrication is reduced. The size and position of these gas flow paths, protrusions, and recesses must be designed with a certain degree of leeway, taking into account the difference in the expansion coefficients of quartz and carbon.

[0060] Generally, reactions between liquids and gases tend to have lower reaction efficiency than reactions between gases because the available surface area for reaction is smaller. Therefore, by providing two first-step reaction zones, unreacted hydrogen chloride in the first zone upstream of the source gas is reacted with gallium in the second zone, maximizing reaction efficiency. Specifically, the overall reaction process is as follows: First, hydrogen chloride-containing gas passes through the outer shell of the second reaction zone, the inside of the insulating quartz material, and the outer shell of the first reaction zone, and flows into the upper section of the first reaction zone where liquid gallium is present, producing a mixed gas of gallium monochloride and hydrogen chloride. This mixed gas passes through the outer shell of the first reaction zone and flows into the lower section of the first reaction zone where liquid gallium is present, where the remaining hydrogen chloride reacts with gallium to produce gallium monochloride gas. This gallium monochloride gas passes through the outer shell of the lower section of the first reaction zone, the inside of the insulating quartz material, and the outer shell of the second reaction zone, and flows into the second reaction zone. Hydrogen chloride that has passed through the outer shell of the second-step reaction compartment also flows into this second-step reaction compartment, where gallium monochloride reacts with hydrogen chloride to produce gallium trichloride gas, which passes through the outer shell of the second-step reaction compartment and is supplied as a film-forming source gas.

[0061] Figure 7 shows an example of a gas system diagram around the gallium trichloride production apparatus shown in Figure 6. The gallium trichloride production apparatus is connected to a source gas line that supplies the mixed gas of hydrogen chloride and hydrogen used in the first and second steps, a product gas line that transports the product gas outside the apparatus and supplies it to the HVPE deposition furnace, a purge gas line that purges the space between the quartz tube and the reaction compartment, and a purge exhaust line that exhausts the purge gas. The source gas line is provided with a section where hydrogen chloride, the flow rate of which is controlled by a flow controller such as a mass flow controller (MFC), and a carrier gas such as hydrogen are joined. This makes it possible to supply hydrogen chloride at any desired concentration into the equipment. The product gas line is also provided with a section where a carrier gas, the flow rate of which is controlled by an MFC or the like, is joined. This makes it possible to transport gallium trichloride at a low concentration, thereby suppressing the precipitation of gallium trichloride crystals during transport to the film formation equipment. It is preferable to install this carrier gas joining section as upstream as possible in the product gas line. Furthermore, it is also preferable to preheat the carrier gas before supplying it to prevent a drop in the temperature of the product gas. The purge gas line sends hydrogen, nitrogen, etc. directly into the quartz tube to wash away any source gases that have leaked out of the reaction zone, preventing damage to the furnace. In addition, when the quartz tube is opened to the atmosphere for maintenance, etc., the hydrogen and other gases inside the furnace can be purged by flowing nitrogen. In addition, flow rate controllers such as MFCs and float needle valves are installed on the line, allowing the flow rate to be adjusted as desired. The product gas line can be heated by a piping heater from the outlet of the gallium trichloride production apparatus to the inlet of the film formation apparatus, and by heating it to preferably 150° C. or higher, more preferably 200° C. or higher, precipitation of gallium trichloride as a solid can be suppressed. In this case, the valve must be heat resistant to temperatures equal to or higher than the heating temperature. A cold trap is installed downstream of the generated gas line. Furthermore, the generated gas flow path to the cold trap and the deposition furnace can be switched to either one using a valve. This allows the generated gas, whose concentration is unstable immediately after the start of raw material supply, to escape to the cold trap, and the generated gas concentration is stabilized before being supplied to the deposition furnace, improving the controllability of the growth rate. The cold trap cools and precipitates gallium trichloride in the generated gas as a solid, minimizing the amount of gallium trichloride gas flowing into the exhaust line, thereby preventing clogging of the exhaust line.

[0062] [Action and effect] According to the method for producing metal trihalide gas of the present invention, at least in the production of gallium trichloride gas, gallium trichloride can be produced at a higher temperature and with higher selectivity than when Ga and hydrogen chloride are reacted in a single step. Furthermore, by generating gallium trichloride gas in situ using high-purity hydrogen chloride gas or a carrier gas and high-purity Ga, gallium trichloride can be supplied with a higher purity than when solid gallium trichloride gas is vaporized and supplied. This prevents raw material loss and clogging of the transport system due to Ga droplet precipitation caused by the disproportionation reaction of gallium monochloride, even in a low-temperature environment during raw material transportation.

[0063] Furthermore, according to the method for producing a metal trihalide gas of the present invention, not only inert gases such as nitrogen but also flammable gases that are undesirable from a safety standpoint in two-stage reactions using chlorine can be safely used as carrier gases, thereby broadening the options for growth conditions. As a specific example, using hydrogen as a carrier gas is expected to improve the crystal growth rate and reduce impurities in GaAs-based crystal growth.

[0064] The semiconductor material gas manufacturing apparatus of the present invention can be used in the same way as conventional semiconductor material gas manufacturing apparatuses that operate at only one reaction temperature, but also enables the execution of a semiconductor material gas reaction process that requires independent control of the first and second stages at any temperature. This broadens the options for generating semiconductor material gases, and can be suitably used, for example, as an apparatus for operating the above-mentioned metal trihalide gas manufacturing method. [Explanation of symbols]

[0065] 100 Semiconductor material gas manufacturing equipment (gallium trichloride manufacturing equipment) C1 Storage Container G0, G0' raw gas G1 First Gas G2 Second Gas H1 First heating mechanism H2 Second heating mechanism H3 Third heating mechanism I1 Heat insulating material L0, L0', L1, L2 gas flow path M1 Solid or liquid raw material S1, S11, S12 First step reaction section S2 Second step reaction section

Claims

1. A method for producing a metal trihalide gas, comprising: a first step of reacting a metal with hydrogen halide to produce a first gas containing a metal monohalide gas; and a second step of reacting the first gas with hydrogen halide to produce a second gas containing a metal trihalide gas, the metal in the first step is gallium or indium, the hydrogen halide in the first step and the second step is hydrogen chloride gas, hydrogen bromide gas, or hydrogen iodide gas; Independently controlling the temperatures at which the first step and the second step are carried out; the reaction temperature in the first step is 400 to 700°C; the reaction temperature in the second step is 300 to 550°C; the temperature in the second step is lower than the temperature in the first step; A method for producing metal trihalide gases.

2. 2. The method for producing a metal trihalide gas according to claim 1, wherein the second gas further contains a metal monohalide gas, and the ratio of the metal monohalide gas to the metal trihalide gas in the second gas is 10 mol % or less.

3. 3. The method for producing a metal trihalide gas according to claim 1, wherein the utilization efficiency of the hydrogen halide after the first step and the second step is 90% or more of the theoretical value.

4. 4. The method for producing a metal trihalide gas according to claim 1, wherein at least one gas selected from the group consisting of nitrogen gas, argon gas, and helium gas is used as a carrier gas for the hydrogen halide.

5. 4. The method for producing a metal trihalide gas according to claim 1, wherein a flammable gas or a mixed gas containing a flammable gas is used as a carrier gas for the hydrogen halide.

6. 6. The method for producing a metal trihalide gas according to claim 5, wherein the combustible gas is hydrogen gas.

7. 7. The method for producing a metal trihalide gas according to claim 4, wherein the ratio of the hydrogen halide to the total number of moles of the hydrogen halide and the carrier gas is 10 mol % or more.

8. The method for producing a metal trihalide gas according to any one of claims 1 to 3, wherein a carrier gas for the hydrogen halide is not used.

9. A semiconductor material gas manufacturing apparatus for using the method for manufacturing a metal trihalide gas according to any one of claims 1 to 8, one or more first stage reaction zones for reacting a feed gas with a solid or liquid feed to produce said first gas; one or more second stage reaction zones for reacting the first gas with a feed gas to produce the second gas; a raw material gas flow path for supplying a raw material gas to the first step reaction compartment and the second step reaction compartment; a first gas flow path for transporting the first gas from the first stage reaction compartment to the second stage reaction compartment; a gas flow path for discharging the second gas from the second step reaction compartment; a first heating mechanism for heating the first step reaction compartment; a second heating mechanism for heating the second step reaction compartment; Equipped with the first heating mechanism and the second heating mechanism are capable of independently controlling the temperatures of the first step reaction compartment and the second step reaction compartment, respectively; Semiconductor material gas manufacturing equipment.

10. 10. The semiconductor material gas manufacturing apparatus according to claim 9, wherein the first reaction compartment and the second reaction compartment are insulated from each other by a vacuum, a gas, or a heat insulating member.

11. a rigid body between the first step reaction compartment and the second step reaction compartment; the rigid body has a gas flow path for transporting the source gas between the first step reaction compartment and the second step reaction compartment; The interior of the rigid body is vacuum or filled with gas or a heat insulating material.

11. The semiconductor material gas manufacturing apparatus according to claim 9 or 10.

12. The first and second process reaction compartments each have at least one first recess or first protrusion on their joint surfaces with the rigid body, The rigid body has at least one second protrusion or second depression B on its joint surface with the first step reaction compartment and the second step reaction compartment; 12. The semiconductor material gas manufacturing apparatus of claim 11, wherein when the rigid body is installed between the first process reaction compartment and the second process reaction compartment, the first recess and the second protrusion or the first protrusion and the second recess are fitted together, and the protruding lengths of the first protrusion and the second protrusion are less than the recessed lengths of the second recess and the first recess, respectively.

13. The semiconductor material gas manufacturing apparatus according to any one of claims 9 to 12, further comprising one or more independently controllable heating mechanisms between the heating mechanism for the first step reaction compartment and the heating mechanism for the second step reaction compartment.

14. 14. The semiconductor material gas manufacturing apparatus according to claim 9, wherein the distance between the first step reaction compartment and the second step reaction compartment is 200 mm or less.

15. The semiconductor material gas manufacturing apparatus according to any one of claims 9 to 14, wherein the first heating mechanism and the second heating mechanism maintain the inside or vicinity of the first step reaction compartment and the second step reaction compartment within a range of the target temperature ±50°C, regardless of whether the first heating mechanism and the second heating mechanism set the first step reaction compartment and the second step reaction compartment to the same target temperature or whether the first heating mechanism and the second heating mechanism set different target temperatures for the first step reaction compartment and the second step reaction compartment.

16. 16. The semiconductor material gas manufacturing apparatus according to claim 15, wherein the different target temperatures are at least two different target temperatures selected from temperatures of 200°C or higher and 1000°C or lower, and the smallest temperature difference among the target temperatures is 50°C or higher.

17. 17. The semiconductor material gas manufacturing apparatus according to claim 9, wherein the material gas produced by reaction in the semiconductor material gas manufacturing apparatus is a source gas used to form a compound semiconductor crystal comprising at least one element selected from the group consisting of Ga and In and at least one element selected from the group consisting of N, As, P, and O, or a crystal obtained by doping the compound semiconductor crystal with an impurity.

18. 18. The semiconductor material gas manufacturing apparatus according to claim 9, further comprising a flow path for introducing a gas into the gas flow path downstream of the second step reaction section.

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