JP4933414B2 - Compound thin film semiconductor manufacturing apparatus and ammonia gas supply apparatus and method - Google Patents

Description

  The present invention relates to a compound thin film semiconductor manufacturing apparatus and an ammonia gas supply apparatus and method, and more specifically, a raw material gas containing ammonia gas is supplied into a reaction chamber, and a thin film semiconductor containing nitride in the reaction chamber, for example, a GaN-based thin film The present invention relates to an apparatus and method for supplying ammonia gas, which is one of source gases, to a compound thin film semiconductor manufacturing apparatus for forming a compound semiconductor in a state where the moisture concentration is sufficiently low.

  In the manufacture of a high-intensity blue light emitting diode (hereinafter referred to as LED), a GaN-based thin film compound semiconductor is generally used. The GaN-based thin film compound semiconductor is manufactured by vapor phase growth (MOCVD) using ammonia and a volatile organic gallium compound such as trimeryl gallium as a raw material. There is a close relationship between the purity of ammonia, which is a raw material gas in the production of a GaN semiconductor thin film, and the luminance of the manufactured LED. In particular, moisture in ammonia causes a decrease in the luminance of the manufactured LED. For this reason, using highly purified ammonia with the water content of 1 ppm or less manufactured with the specific manufacturing method as a raw material is performed (for example, refer patent document 1).

  When ammonia is used as a source gas, a high-pressure gas container filled with ammonia is usually used as a supply source. The vapor pressure of ammonia at 25 ° C. is about 0.9 MPa (absolute pressure), and the high-pressure gas container is filled with liquefied high-pressure gas partially liquefied in this high-pressure gas container. For supplying ammonia from the high-pressure gas container to the compound thin film semiconductor manufacturing apparatus, stainless steel pipes having excellent corrosion resistance and pressure resistance are generally used. In compound thin film semiconductor manufacturing equipment, the operating pressure of ammonia gas is from atmospheric pressure to reduced pressure, so a pressure regulator is used in the supply system, and a multilayer thin film is grown in the manufacturing process and adjusted to a flow rate suitable for that process. Because it is necessary to do this, a mass flow controller or the like is used. In addition, there are many cases where a pressure gauge is installed to check the supply state of ammonia gas as appropriate, and safety equipment and parts are often installed, and the piping length from the high-pressure gas container to the compound thin film semiconductor manufacturing equipment is very large. It is long and ranges from several to several tens of meters.

In the step of replacing the high pressure gas container, in view of the toxicity of ammonia gas, a purge operation with an inert gas such as nitrogen is performed before removing the high pressure gas container from the pipe. This purge operation is performed to remove ammonia remaining in the piping of the ammonia gas supply system and replace it with a non-toxic inert gas. Furthermore, when installing a high-pressure gas container, air is taken into the pipe, and therefore, purging with an inert gas is performed in the same manner as when removing the air component to remove air components and moisture in the air. . In addition to the replacement of the high-pressure gas container, when opening a portion connected to the supply system piping, such as a supply system malfunction or parts replacement, a purge operation with an inert gas is always performed before and after that.
Japanese Patent No. 3818051 (Claims 2 and 3)

  When using high-purity ammonia as a raw material as described above, the present inventor supplied ammonia gas after purging piping for supplying ammonia gas with dry nitrogen having a moisture concentration of 0.1 to 1 ppb. The present inventors have found that the water concentration rapidly rises even though the water concentration in the high-pressure gas container storing the ammonia gas to be supplied is 10 ppb or less. This sudden rise in moisture concentration is much higher than the moisture concentration in the ammonia gas to be supplied and the inert gas used for the purge operation, and is due to the difference in the adsorption characteristics of ammonia, nitrogen, water, and stainless steel pipe surfaces. Presumed to be. Since this phenomenon occurs, for example, even if the water concentration in the ammonia used is extremely low, high concentration water is mixed into the compound thin film semiconductor manufacturing apparatus in the initial stage of supply.

  Furthermore, as described above, ammonia used by being filled in a high-pressure gas container is a part of the container liquefied at room temperature, and the moisture in ammonia has a concentration between the liquid phase part and the gas phase part. Different. Since water has a higher boiling point than ammonia, the water concentration in the gas phase is sufficiently lower than that in the liquid phase. For this reason, when the gas phase part is led out from the container, the water concentration can be kept low, but a concentration phenomenon occurs in which the water concentration in the liquid phase part increases. It is known that the water concentration of the part also increases gradually. Further, when the gas is led out from the high-pressure gas container, the amount of heat corresponding to the latent heat of evaporation when the liquefied ammonia evaporates reduces the temperature of the liquid phase. For this reason, the temperature of the liquid phase portion in the high pressure gas container is lowered, bumping occurs in the high pressure gas container, and the liquid phase portion having a high moisture concentration is released.

  The temperature of the liquid phase part in the high-pressure gas container has a large temperature drop because the amount of heat necessary for evaporation per hour increases as the supply amount increases. Further, when the remaining amount of ammonia in the high-pressure gas container is reduced, the volume of the liquid phase portion having a large thermal conductivity is relatively reduced, so that the temperature drop is increased. For this reason, the temperature change of ammonia in the high-pressure gas container greatly depends on the derived flow rate, the remaining amount, and the environmental temperature.

  For this reason, when a high-pressure gas container filled with high-purity ammonia is used as a source gas supply source in MOCVD, purging with an inert gas is possible even if the moisture concentration in the ammonia gas is extremely low. When the supply of ammonia is started after it has been performed, the moisture concentration suddenly rises in the initial stage of supply, as well as the flow rate of ammonia from the high pressure gas container, the liquid phase remaining in the high pressure gas container, the temperature in the container, and the purge operation There has been a problem that the water concentration in ammonia at the time of supply varies depending on the amount of inert gas used, the time from the end of the purge operation to the start of ammonia gas supply, the environmental temperature, and the like.

  Therefore, even if ammonia filled in the high-pressure gas container serving as a source gas supply source is made high purity and the water concentration is lowered to the limit, there is a possibility that high concentration of water may be mixed in the compound thin film semiconductor manufacturing apparatus, and it is manufactured. It will adversely affect the quality and performance of compound thin film semiconductors.

  Therefore, the present invention can sufficiently suppress the mixing of moisture into a compound thin film semiconductor manufacturing apparatus that uses ammonia gas as one of the source gases, and manufactures a high quality and high performance compound thin film semiconductor in a stable state. It is an object of the present invention to provide a compound thin film semiconductor manufacturing apparatus and an ammonia gas supply apparatus and method that can be used.

  To achieve the above object, a compound thin film semiconductor manufacturing apparatus of the present invention is a compound thin film semiconductor manufacturing apparatus that supplies a source gas containing ammonia gas into a reaction chamber and forms a nitride thin film semiconductor in the reaction chamber. The ammonia gas supply path for supplying the ammonia gas into the reaction chamber includes a moisture meter provided in the ammonia gas inlet path of the reaction chamber, and a plurality of ammonia gas supplies joined to the ammonia gas inlet path on the upstream side of the moisture meter A plurality of ammonia gas supply systems, an ammonia gas supply source, a supply pipe connecting the ammonia gas supply source and the ammonia gas inlet path, and the ammonia gas inlet path in the supply pipe A supply valve provided on the upstream side of the connection portion, an exhaust path branched from the upstream side of the supply valve, and provided in the exhaust path Supplying one system among the plurality of ammonia gas supply systems, each having an exhaust valve and opening and closing the supply valve and the exhaust valve in the plurality of ammonia gas supply systems based on the measured value of the moisture meter Open the valve and close the exhaust valve to supply ammonia gas from one ammonia gas supply system to the reaction chamber, close the supply valve of the other ammonia gas supply system, and open the exhaust valve to supply other ammonia gas The system includes an ammonia gas supply control unit that performs a purge operation for discharging ammonia gas from the ammonia gas supply source to the exhaust path.

  Further, the ammonia gas supply apparatus of the present invention is the ammonia gas supply apparatus for supplying the ammonia gas to the compound thin film semiconductor manufacturing apparatus for forming a thin film semiconductor containing nitride using a source gas containing ammonia gas. A moisture meter provided in the ammonia gas inlet path of the compound thin film semiconductor manufacturing apparatus, and a plurality of ammonia gas supply systems that merge with the ammonia gas inlet path on the upstream side of the moisture meter, the plurality of ammonia gas supply systems An ammonia gas supply source, a supply pipe connecting the ammonia gas supply source and the ammonia gas inlet path, and a supply valve provided on the upstream side of the connection portion of the ammonia gas inlet path in the supply pipe; Each provided with an exhaust path branched from the upstream side of the supply valve and an exhaust valve provided in the exhaust path; Based on the measured value of the moisture meter, the supply valve and the exhaust valve in the plurality of ammonia gas supply systems are opened and closed, one of the plurality of ammonia gas supply systems is opened, and the exhaust valve is closed. The ammonia gas is supplied from one ammonia gas supply system to the reaction chamber, the supply valve of the other ammonia gas supply system is closed, the exhaust valve is opened, and the other ammonia gas supply system is connected to the ammonia gas supply source. The ammonia gas supply control part which performs the purge operation which discharges | emits ammonia gas to the said exhaust path is provided.

In addition, the ammonia gas supply how the present invention is a method of supplying ammonia gas to the compound thin film semiconductor manufacturing apparatus for forming a thin film semiconductor which includes a nitride using a source gas containing ammonia gas, the compound thin film When a plurality of ammonia gas supply systems for supplying ammonia gas to the semiconductor manufacturing apparatus are provided, and when ammonia gas is supplied from one system to the compound thin film semiconductor manufacturing apparatus, the other In the ammonia gas supply system, a purge operation for flowing ammonia gas through the supply pipe and discharging it outside the system is performed, the moisture concentration in the ammonia gas supplied to the compound thin film semiconductor manufacturing apparatus is measured, and the measured moisture When the concentration rises to the preset upper limit moisture concentration, the compound thin film semiconductor manufacturing apparatus It stops the supply of ammonia gas from the ammonia gas supply system that supplies gas, is characterized by starting the supply of ammonia gas from the other of the ammonia gas supply system is performing the purge operation.

Further, characterized ammonia gas supply method of the present invention, prior Ki構 formed, a purge operation by the ammonia gas, to begin after the purging operation using purge gas, the upper limit water concentration is 50ppb In addition, the purge operation with the ammonia gas of the other ammonia gas supply system has started to increase the water concentration in the ammonia gas supplied to the compound thin film semiconductor manufacturing apparatus and increased to a preset intermediate water concentration When, preferably, it starts when the intermediate moisture concentration rises to 30 ppb.

  According to the present invention, before the supply of ammonia gas to the compound thin film semiconductor manufacturing apparatus is started, the supply pipe is purged with ammonia gas, and the gas whose moisture concentration has increased when the supply of ammonia gas is started is discharged out of the system. Thus, ammonia gas with a high water concentration does not flow into the compound thin film semiconductor manufacturing apparatus, and a high quality and high performance compound thin film semiconductor can be manufactured in a stable state.

  FIG. 1 is a system diagram of an essential part showing an embodiment of the compound thin film semiconductor manufacturing apparatus of the present invention incorporating the ammonia gas supply apparatus of the present invention. The ammonia gas supply device incorporated in the compound thin film semiconductor manufacturing apparatus is for supplying high purity ammonia gas having a sufficiently low moisture concentration to the reaction chamber (chamber) 11 of the compound thin film semiconductor manufacturing apparatus. The two ammonia gas supply systems 21 and 31 are provided for one ammonia gas inlet path 12 connected to the raw material gas inlet section, and the ammonia gas supply control section 41 for switching the ammonia gas supply systems 21 and 31 to be used. It has. In FIG. 1, a system for supplying other source gas and purge gas to the reaction chamber 11 is not shown.

  The ammonia gas inlet path 12 is provided with a moisture meter 13 for measuring the amount of moisture in the ammonia gas flowing through the path, and a purifier 14 for removing moisture in the ammonia gas. A purification inlet valve 15 a and a purification outlet valve 15 b are provided before and after the purifier 14, and a bypass valve 16 is provided for supplying ammonia gas directly to the reaction chamber 11 without passing through the purifier 14.

  Each ammonia gas supply system 21, 31 includes an ammonia gas supply source 22, 32, a supply pipe 23, 33 connecting the ammonia gas supply source 22, 32 and the ammonia gas inlet path 12, and the supply pipe 23, 33, supply valves 24 and 34 provided on the upstream side of the connecting portion 12a (joining portion of the ammonia gas supply systems 21 and 31) to the ammonia gas inlet path 12, and branching from the upstream side of the supply valves 24 and 34 Exhaust passages 25, 35, exhaust valves 26, 36 provided in the exhaust passages 25, 35, supply source valves 27, 37 provided at the outlets of the ammonia gas supply sources 22, 32, and supply piping 22 , 32 for performing a purge operation, and purge valves 29, 39 provided in the purge gas introduction paths 28, 38, respectively. That.

  As the ammonia gas supply sources 22 and 32, high-pressure gas containers filled with high-purity ammonia having a sufficiently low moisture concentration are used, and ammonia gas is supplied in a state of being installed in a well-known cylinder cabinet. Yes. When the high-pressure gas container is installed in a known cylinder cabinet, the replacement of the high-pressure gas container with a small remaining amount is performed on the upstream side of the supply source valves 27 and 37 by a known replacement procedure including gas replacement and purging. Is called.

  The ammonia gas supply control unit 41 supplies the reaction chamber 11 by switching and opening and closing the supply valves 24 and 34 and the exhaust valves 26 and 36 according to the moisture concentration in the ammonia gas measured by the moisture meter 13. A system switching operation for switching the ammonia gas supply system to one of the ammonia gas supply systems 21 and 31, and a purge operation using the purge gas for introducing and exhausting the purge gas from the purge gas introduction paths 28 and 38 into the supply pipes 23 and 33 And the ammonia purge operation by the ammonia gas that is introduced into the supply pipes 23 and 33 and exhausted from the ammonia gas supply sources 22 and 32. The upper limit moisture concentration and the intermediate moisture concentration are obvious as setting values for starting each operation. It is because setting.

  Although it is possible to use what was described in the said patent document 1 for the moisture meter 13, since the capacity | capacitance of a gas cell is large, measurement time takes long, and the moisture concentration contained in the ammonia gas currently supplied is taken. It is difficult to capture changes over time. Therefore, it is possible to use an analyzer utilizing cavity ring-down spectroscopy (CRDS) that can measure the moisture concentration in ammonia gas in a short time and can accurately grasp the change in moisture concentration over time. preferable. Moreover, as the purifier 14, various commercially available purifiers that can remove moisture in the ammonia gas can be used.

  In addition, the ammonia gas supply device of the present invention can be used for the purpose of supplying high-purity ammonia gas to other devices in addition to being incorporated in a compound thin film semiconductor manufacturing device. The purifier 14 is not essential, and the purifier 14 including the purification inlet valve 15a, the purification outlet valve 15b, and the bypass valve 16 can be omitted.

  An experiment was conducted to form a GaN-based thin film compound semiconductor using the compound thin film semiconductor manufacturing apparatus incorporating the ammonia gas supply apparatus having the configuration shown in FIG. First, using one ammonia gas supply system 21, a nitrogen purge operation using nitrogen as an inert gas (dry high purity nitrogen gas) as a purge gas, and an ammonia gas for supplying ammonia gas from an ammonia gas supply source 22 The supply operation was repeated, and the change in the moisture concentration in the gas (nitrogen, ammonia) flowing through the ammonia gas inlet passage 12 was measured with the moisture meter 13. The result is shown in FIG.

  From this result, it can be seen that the moisture concentration measured by the moisture meter 13 rapidly increases when the nitrogen purge operation is switched to the ammonia gas supply operation. Accordingly, in the film forming operation in the compound thin film semiconductor manufacturing apparatus, the conventional general ammonia gas supply is performed by sufficiently purging the inside of each path by the nitrogen purge operation and reducing the water concentration to about 4 ppb before switching to the ammonia gas supply operation. In the method, even if the moisture concentration in the ammonia gas supplied from the ammonia gas supply source 22 is sufficiently low, high concentration moisture enters the reaction chamber 11 when switching from the nitrogen purge operation to the ammonia gas supply operation. Thus, it can be seen that there is a possibility of causing the performance deterioration of the GaN-based thin film compound semiconductor to be formed.

  Next, a 25-liter manganese steel container filled with 25 kg of high-purity ammonia was used as the ammonia gas supply source 22, and the change in moisture concentration was measured when ammonia gas was continuously supplied at 1 liter per minute. The result is shown in FIG. From this result, it can be seen that when the remaining amount of ammonia in the container is 500 g or less, the moisture concentration starts to increase, and when the remaining amount is about 300 g, it rapidly increases. When the remaining amount reached 300 g, the temperature of the liquid phase portion was 4 ° C. lower than room temperature.

  Also, after supplying ammonia gas continuously at 1 liter per minute until the remaining amount of ammonia reaches 5 kg, the flow rate is changed to 5 liters per minute, 10 liters per minute, and 1 liter per minute. The change in water concentration was measured. The result is shown in FIG. From this result, it can be seen that the water concentration in the ammonia gas varies depending on the supplied flow rate.

  For these reasons, even if the moisture concentration in the ammonia gas in the ammonia gas supply source 22 is strictly controlled, the moisture concentration in the ammonia gas supplied to the reaction chamber 11 of the compound thin film semiconductor manufacturing apparatus cannot be sufficiently managed. I understand.

On the other hand, moisture is added to the ammonia gas supplied to the reaction chamber 11 to change the moisture concentration in five stages, a GaN-based thin film compound semiconductor having a structure shown in FIG. 5 is formed, and a high-intensity blue LED is manufactured. The brightness of was measured. Table 1 shows the relationship between the water concentration in ammonia gas and the luminance of the high-intensity blue LED (relative value with the luminance being 100 when the water concentration is less than 10 ppb). The moisture concentration is adjusted by adding a predetermined amount of moisture to ammonia gas with a constant moisture concentration through a purifier different from the purifier 14, and the moisture meter 13 is used during film formation. The water concentration was confirmed continuously.

  From the results shown in Table 1, it can be seen that the luminance decreases as the moisture concentration in the ammonia gas increases.

Similarly, ammonia gas to which water has been added is supplied to the reaction chamber 11 through the purifier 14 provided in the ammonia gas inlet path 12, and the same GaN-based thin film compound semiconductor is formed to produce a high-intensity blue LED. did. Table 2 shows the relationship between the water concentration in the ammonia gas before purification and the luminance of the high-intensity blue LED (the relative value when the water concentration before purification is less than 10 ppb is 100).

  From the results shown in Table 2, even if the water concentration in the ammonia gas supplied from the ammonia gas supply source 22 changes, a high-intensity blue LED with the same luminance can be obtained by sufficiently reducing the water concentration through the purifier. I understand that

In addition, the amount of ammonia in a 47-liter manganese steel container similar to that described above is 25 kg, the water concentration in the liquid phase is 100 ppb and 1000 ppb, respectively, and the amount of ammonia is 3 kg and the water concentration in the liquid phase is respectively 100 ppb and 1000 ppb ones were prepared and supplied to the reaction chamber 11 to form a GaN-based thin film compound semiconductor similar to the above to produce a high-intensity blue LED. Table 3 shows the relationship between the amount of ammonia in the container, the water concentration, and the luminance (relative value with the luminance being 100 when the weight in the container is 25 kg and the water concentration in the liquid phase is 100 ppb).

  From the results in Table 3, the water concentration in the liquid phase of ammonia in the container hardly affects the luminance of the blue LED, but the decrease in the weight (remaining amount) of ammonia in the container affects the luminance of the blue LED. You can see that

  Next, using both ammonia gas supply systems 21 and 31, an ammonia gas supply device having an ammonia gas supply source 22 and 32 by attaching the same 47-liter manganese steel container filled with 25 kg of ammonia was used. In addition, ammonia gas is continuously supplied from one ammonia gas supply system (hereinafter referred to as the first ammonia gas supply system) 21 to the reaction chamber 11 in the atmospheric pressure state at a flow rate of 5 liters per minute, and the change in moisture concentration at that time is measured. It was measured. In supplying ammonia gas, first, the exhaust valve 26 and the purge valve 29 are opened from a state in which all the valves are closed, and nitrogen having a moisture concentration of 5 ppb or less is introduced into the supply pipe 23 from the purge gas introduction path 28. After purging nitrogen from the system 25 and purging atmospheric components and moisture in the supply pipe 23 sufficiently with nitrogen, the exhaust valve 26 and purge valve 29 are closed, and the supply source valve 27 and supply valve 24 are closed. The bypass valve 16 was opened, and ammonia gas was supplied from the ammonia gas supply source 22 to the reaction chamber 11 via the supply pipe 23 and the ammonia gas inlet path 12. FIG. 6 shows the change over time in the moisture concentration measured by the moisture meter 13 at this time. In the other ammonia gas supply system (hereinafter referred to as the second ammonia gas supply system) 31, the exhaust valve 36 and the purge valve 39 were opened to continue the nitrogen purge.

  As is clear from FIG. 6, immediately after switching from the purge operation with nitrogen gas to the ammonia gas supply operation, the water concentration suddenly increases, and then the water concentration decreases and becomes stable at several ppb. It can be seen that the moisture concentration increases when the amount of ammonia remaining in the container decreases. Therefore, immediately after switching from the purge operation with nitrogen gas to the ammonia gas supply operation, the purge valve 29 is closed and the supply source valve 27 is opened, and flows into the supply pipe 23 from the ammonia gas supply source 22 through the supply source valve 27. A purge operation with ammonia gas that discharges ammonia gas out of the system from the exhaust path 25 is performed, and after a predetermined time has elapsed, or when a moisture meter is installed in the exhaust path 25, the moisture concentration measured by the moisture meter is a predetermined concentration. After dropping to the following, the supply of ammonia gas to the reaction chamber 11 is started by closing the exhaust valve 26 and opening the supply valve 24, and the water concentration measured by the moisture meter rises to a preset upper limit concentration In this case, the supply of ammonia gas to the reaction chamber 11 is stopped to prevent moisture from being brought into the reaction chamber 11. Door can be. However, when the supply of ammonia gas to the reaction chamber 11 is stopped in this way, there arises a problem that the film forming operation is interrupted.

  Therefore, 50 ppb was set as the upper limit water concentration in the ammonia gas supply control unit 41 and 30 ppb was set as the intermediate water concentration, and the ammonia gas was supplied to the reaction chamber 11 by controlling the opening and closing of each valve by the ammonia gas supply control unit 41. . FIG. 7 shows the change over time in the moisture concentration in the ammonia gas measured by the moisture meter 13 at this time. 7A shows a state in which ammonia gas is continuously supplied from the first ammonia gas supply system 21 to the reaction chamber 11 in the atmospheric pressure state at a flow rate of 5 liters per minute. The state of each valve at this time is as follows: bypass valve 16 of the ammonia gas inlet path 12, supply valve 27 and supply valve 24 of the first ammonia gas supply system 21, exhaust valve 36 and purge valve of the second ammonia gas supply system 31 39 is open, and the other valves are closed. In the second ammonia gas supply system 31, a nitrogen purge operation is performed.

  Similar to FIG. 6, the water concentration rapidly increasing immediately after switching to the ammonia gas supply operation decreases with time, stabilizes at a low concentration, and then the water concentration decreases due to the decrease in the remaining amount of ammonia in the container. Begins to rise. When the moisture concentration measured by the moisture meter 13 rises to 30 ppb, which is the intermediate moisture concentration, the ammonia gas supply control unit 41 closes the purge valve 39 of the second ammonia gas supply system 31 and opens the supply source valve 37, In the ammonia gas supply system 31, a purge operation by the ammonia gas that discharges the ammonia gas flowing into the supply pipe 33 from the ammonia gas supply source 32 through the supply source valve 37 through the exhaust path 35 to the outside of the system is started. At this time, as shown in FIG. 7B, the moisture concentration measured by the moisture meter 13 continues to rise, but the moisture concentration in the ammonia gas discharged from the second ammonia gas supply system 31 to the outside of the system is As shown by a broken line in FIG. 7, it is in a state of gradually decreasing after a sudden rise.

  When the moisture concentration measured by the moisture meter 13 increases to the upper limit moisture concentration of 50 ppb, the ammonia gas supply control unit 41 operates to supply the ammonia gas to the reaction chamber 11 as the first ammonia gas supply system 21. To the second ammonia gas supply system 31. That is, in the first ammonia gas supply system 21, the supply source valve 27 and the supply valve 24 are closed, and in the second ammonia gas supply system 31, the exhaust valve 36 is closed and the supply valve 34 is opened. As a result, the reaction chamber 11 is supplied with ammonia gas from the ammonia gas supply source 32 of the second ammonia gas supply system 31 through the supply pipe 33 and the ammonia gas inlet path 12, and FIG. As shown in FIG. 4, the moisture concentration measured by the moisture meter 13 gradually decreases and becomes stable at a low concentration.

  Thus, the purifier can be used without interrupting the supply of ammonia gas to the reaction chamber 11 by controlling the opening and closing of each valve by the ammonia gas supply control unit 41 according to the moisture concentration measured by the moisture meter 13. Without ammonia gas having a water concentration of 50 ppb or less.

  The set values of the upper limit moisture concentration and the intermediate moisture concentration are the rising state of the moisture concentration at the start of supply, the subsequent reduction state, the rising state due to the decrease in the remaining amount in the container, the ammonia gas inlet path 12 and the supply pipes 23 and 33 It is set according to the length and diameter, supply flow rate and pressure, flow rate change and pressure change during supply, maximum moisture concentration allowed for film forming operation, and other conditions. It is not limited. Further, when the supply amount of ammonia gas is large, three or more ammonia gas supply systems can be provided.

It is a systematic diagram of the principal part which shows one example of the compound thin film semiconductor manufacturing apparatus of this invention incorporating the ammonia gas supply apparatus of this invention. It is a figure which shows the change of a moisture concentration when repeating nitrogen purge operation and ammonia gas supply operation. It is a figure which shows the relationship between the residual gas weight in a container when an ammonia gas is supplied continuously, and a water concentration. It is a figure which shows the change of a water concentration when changing a flow volume. It is a figure which shows the structure of the formed GaN-type thin film compound semiconductor. It is a figure which shows the time-dependent change of a water concentration when ammonia gas is continuously supplied to the reaction chamber. It is a figure which shows a time-dependent change of a water concentration when operating an ammonia gas supply control part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Reaction chamber, 12 ... Ammonia gas inlet path, 12a ... Connection part, 13 ... Moisture meter, 14 ... Purifier, 15a ... Purification inlet valve, 15b ... Purification outlet valve, 16 ... Bypass valve, 21, 31 ... Ammonia gas Supply system, 22, 32 ... ammonia gas supply source, 23, 33 ... supply piping, 24, 34 ... supply valve, 25, 35 ... exhaust path, 26, 36 ... exhaust valve, 27, 37 ... supply source valve, 28, 38 ... Purge gas introduction path, 29, 39 ... Purge valve, 41 ... Ammonia gas supply controller

Claims (7)

In the compound thin film semiconductor manufacturing apparatus for supplying a raw material gas containing ammonia gas into a reaction chamber, and forming a thin film semiconductor containing nitride in the reaction chamber, the ammonia gas supply path for supplying the ammonia gas into the reaction chamber includes: A moisture meter provided in the ammonia gas inlet path of the reaction chamber; and a plurality of ammonia gas supply systems that merge with the ammonia gas inlet path on the upstream side of the moisture meter. A supply source, a supply pipe connecting the ammonia gas supply source and the ammonia gas inlet path, a supply valve provided upstream of a connection portion of the supply pipe with the ammonia gas inlet path, and the supply valve And an exhaust valve provided in the exhaust path, respectively, and based on the measured value of the moisture meter. Open and close the supply valve and the exhaust valve in the plurality of ammonia gas supply systems, open the supply valve of one of the plurality of ammonia gas supply systems, and close the exhaust valve from one ammonia gas supply system Supply ammonia gas to the reaction chamber, close the supply valve of the other ammonia gas supply system, open the exhaust valve, and in the other ammonia gas supply system, ammonia gas from the ammonia gas supply source enters the exhaust path An apparatus for manufacturing a compound thin film semiconductor, comprising an ammonia gas supply control unit for performing a purge operation for discharging. In the ammonia gas supply apparatus for supplying the ammonia gas to the compound thin film semiconductor manufacturing apparatus for forming a thin film semiconductor containing nitride by using a source gas including ammonia gas, the ammonia gas supply apparatus has an ammonia gas inlet path in the compound thin film semiconductor manufacturing apparatus. And a plurality of ammonia gas supply systems that merge with the ammonia gas inlet path upstream of the moisture meter, the plurality of ammonia gas supply systems comprising an ammonia gas supply source, and the ammonia gas supply system. A supply pipe connecting the source and the ammonia gas inlet path, a supply valve provided upstream of the connection portion of the supply pipe with the ammonia gas inlet path, and an exhaust path branched from the upstream side of the supply valve And an exhaust valve provided in the exhaust path, respectively, and the plurality of controllers based on the measured value of the moisture meter. Open and close the supply valve and the exhaust valve in the Monia gas supply system, open the supply valve of one of the plurality of ammonia gas supply systems, and close the exhaust valve to transfer the reaction from the ammonia gas supply system to the reaction chamber. A purge operation is performed to supply ammonia gas, close the supply valve of the other ammonia gas supply system, open the exhaust valve, and discharge the ammonia gas from the ammonia gas supply source to the exhaust path in the other ammonia gas supply system. An ammonia gas supply device comprising an ammonia gas supply control unit for performing the operation. An ammonia gas supply system for supplying ammonia gas to the compound thin film semiconductor manufacturing apparatus in a method of supplying ammonia gas to a compound thin film semiconductor manufacturing apparatus for forming a nitride thin film semiconductor using a source gas containing ammonia gas When supplying ammonia gas from one of the plurality of ammonia gas supply systems to the compound thin film semiconductor manufacturing apparatus, the other ammonia gas supply systems use ammonia gas in the supply piping. When the water concentration in the ammonia gas supplied to the compound thin film semiconductor manufacturing apparatus is measured and the measured water concentration rises to a preset upper limit water concentration An ammonia gas supply system for supplying ammonia gas to the compound thin film semiconductor manufacturing apparatus It stops the supply of al of ammonia gas, ammonia gas supply method characterized by starting the supply of ammonia gas from the other of the ammonia gas supply system is performing the purge operation. The purge operation by ammonia gas, supply method according to claim 3 Symbol placement of the ammonia gas, characterized in that to start after the purging operation using purge gas. The method for supplying ammonia gas according to claim 3 or 4, wherein the upper limit moisture concentration is 50 ppb. The purge operation with the ammonia gas of the other ammonia gas supply system starts when the moisture concentration in the ammonia gas supplied to the compound thin film semiconductor manufacturing apparatus starts to rise to a preset intermediate moisture concentration. The method for supplying ammonia gas according to any one of claims 3 to 5 , wherein: The method for supplying ammonia gas according to claim 6, wherein the intermediate moisture concentration is 30 ppb.

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