JP2010062383A - Vapor deposition equipment and vapor deposition method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve film deposition under various conditions by adjusting the size of a mixing chamber. <P>SOLUTION: Vapor deposition equipment 1 includes a shower plate 2 which is disposed opposite a substrate holding member 16 where a substrate 15 to be processed in a reactor 14 is placed and held and which supplies a first gas toward the substrate 15 to be processed, and a shower plate 3 which is disposed on the opposite side of the substrate holding member 16 with respect to the shower plate 2 and supplies a second gas toward the substrate 15 to be processed. The shower plate 2 has a gas flow passage 4a in which the first gas flows toward the substrate 15 to be processed, and the shower plate 3 has a gas conduit 5 which projects from the shower plate 3 and is inserted into the gas flow passage 4a and in which the second gas flows toward the substrate 15 to be processed, the space formed of the gas flow passage 4a and gas conduit 5 is different in configuration between the center and peripheral edge of the shower plate 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vapor phase growth comprising a shower plate disposed to face a substrate holding member for placing a substrate to be processed in a reaction furnace and provided to supply gas toward the substrate to be processed. The present invention relates to an apparatus and a vapor phase growth method.

Conventionally, in the manufacture of light emitting diodes and semiconductor lasers, organometallic gases such as trimethylgallium (TMG) or trimethylaluminum (TMA), and ammonia (NH ₃ ), phosphine (PH ₃ ), arsine (AsH ₃ ), etc. An MOCVD (Metal Organic Chemical Vapor Deposition) method and an MOCVD apparatus are used in which a hydrogen compound gas is introduced into a growth chamber as a source gas contributing to film formation to grow a compound semiconductor crystal.

  The MOCVD method is a method for growing a compound semiconductor crystal on a substrate to be processed by introducing the source gas together with an inert gas into a growth chamber and heating it to cause a gas phase reaction on the substrate to be processed. is there. In the production of compound semiconductor crystals using MOCVD, there is always a high demand for how to secure the maximum yield and production capacity while reducing costs while improving the quality of growing compound semiconductor crystals. Has been.

  FIG. 14 shows a schematic configuration of an example of a conventional vertical shower head type MOCVD apparatus used in the MOCVD method. In this MOCVD apparatus, a gas pipe 93 for introducing a reaction gas and an inert gas from a gas supply source 92 to a growth chamber inside the reaction furnace 91 is connected, and a growth chamber 81 inside the reaction furnace 91 is connected. A shower plate 90 having a plurality of gas discharge holes for introducing a reaction gas and an inert gas into the growth chamber is installed as a gas introduction part. In addition, a rotary shaft 82 that is rotatable by an actuator (not shown) is installed in the center of the growth chamber 81 of the reaction furnace 91, and a susceptor 98 is provided at the tip of the rotary shaft 82 so as to face the shower plate 90. A heater 99 for heating the susceptor 98 is attached to the lower part of the susceptor 98. A gas exhaust part 94 for exhausting the gas in the growth chamber 81 inside the reaction furnace 91 to the outside is installed at the lower part of the reaction furnace 91, and the gas exhaust part 94 is connected via a purge line 95. The exhaust gas treatment device 96 for detoxifying the exhausted gas is connected.

  In the vertical showerhead type MOCVD apparatus having the above-described configuration, the substrate 97 is placed on the susceptor 98 when the compound semiconductor crystal is grown, and then the susceptor 98 is rotated by the rotation of the rotating shaft 82. Then, the substrate 97 is heated to a predetermined temperature through the susceptor 98 by the heating of the heater 99, and the reaction gas and non-reactant gas are supplied from the plurality of gas discharge holes formed in the shower plate 90 to the growth chamber 81 inside the reaction furnace 91. An active gas is introduced.

As a method of forming a thin film by supplying a plurality of reaction gases and reacting them on a substrate to be processed, conventionally, a plurality of gases are mixed in a shower head, and are covered from gas discharge ports provided in a large number on the shower plate. A method has been adopted in which a reactive gas is blown out onto a processing substrate. However, according to the above method, in the reaction furnace 91, the gas flowing from the shower plate 90 is exhausted in the radial direction of the susceptor 98, so the supply of the material gas cannot catch up at the center of the susceptor 98, There is a tendency that a shortage occurs, the gas flows in the radial direction before the reaction of the gas, or the film forming rate tends to decrease at the central portion.
In order to solve this problem, in Patent Document 1, gas is introduced into a reaction furnace from a nozzle in which a plurality of gas flow paths are formed coaxially, thereby efficiently mixing on the upper surface of the substrate while preventing clogging of the nozzle. A method for improving material efficiency is shown.
Patent Document 2 discloses a method for improving the film quality by preventing the reaction at the central portion from becoming insufficient by increasing the distribution density of the nozzle at the central portion rather than the peripheral portion. Has been.
JP 2000-144432 A (published May 26, 2000) Japanese Patent Laid-Open No. 8-035067 (published February 6, 1996)

In film formation of compound semiconductor crystals, high uniformity is required in film thickness distribution and film quality in order to improve quality. In addition, in order to reduce costs, it is necessary to improve material efficiency, yield, and productivity. However, according to the method disclosed in Patent Document 1, the reaction is insufficient in the central portion in the range where the gas is ejected by the shower head, the film quality and the film formation rate are lowered, the quality and yield of the film formation substrate, and the productivity. May fall.
Further, according to the method disclosed in Patent Document 2, a shower head having a different number of nozzles or different nozzle diameters is used in the central portion and the peripheral portion. In either case, the portion other than the nozzles is reduced. For this reason, there is a possibility that the cost of the shower plate may increase due to the necessity of high-precision processing so as not to communicate between the nozzles. In addition, in a shower plate having a cooling layer between nozzles, the space that can be used as a cooling layer other than the nozzle is reduced when the nozzle density is increased, so that the cooling medium is also reduced. For example, when water is used as the cooling medium, the amount of water flowing in the cooling layer is reduced, so that a cooling difference occurs in the shower plate, and the film quality and film pressure distribution may be nonuniform. Moreover, if the space of the cooling layer of the shower plate is provided uniformly in accordance with the portion where the nozzle density is high, the space of the cooling layer is reduced and the cooling effect is lowered. Therefore, a growth reaction occurs in the shower plate, and there is a possibility that the material efficiency and the film quality are lowered.
In an actual apparatus, film forming conditions and film forming regions are often changed according to a desired film forming rate and film quality. At that time, the optimum nozzle distribution density varies depending on the film formation conditions and film formation region. However, in Patent Document 2, it is difficult to change the nozzle distribution density unless the shower head is replaced. If the shower head is replaced, the main part of the device is replaced, which requires complicated and time-consuming operations such as shaft adjustment. Furthermore, the shower head itself is expensive due to its resistance to heat, gas, etc. In many cases, it is made of a member, and there is a problem that it costs much if several kinds of shower heads are prepared. Further, when the shower head is not exchanged, there is a problem that optimization of the film formation conditions becomes difficult because the film formation conditions and the film formation region are limited.
Furthermore, according to the configuration of Patent Document 2, since there is no mixing chamber and the miscibility of different kinds of gases is low, the gas phase reaction is not performed uniformly, and the film quality and film thickness distribution may be uneven. There is.

  In view of the above circumstances, an object of the present invention is to provide a vapor phase growth apparatus and a vapor phase growth method capable of making the film formation rate and film quality of a substrate uniform.

  A vapor phase growth apparatus according to the present invention includes a first shower plate that is disposed to face a substrate holding member on which a substrate to be processed in a reaction furnace is placed and supplies a first gas toward the substrate to be processed. A vapor phase growth apparatus comprising: a second shower plate disposed on an opposite side of the substrate holding member with respect to the first shower plate and supplying a second gas toward the substrate to be processed; A gas flow path through which the first gas flows toward the substrate to be processed is formed in one shower plate, and the second shower plate protrudes from the second shower plate and enters the gas flow path. A gas conduit that is inserted and allows the second gas to flow toward the substrate to be processed, and is formed by the gas flow path and the gas conduit at the center and the periphery of the first shower plate; Wherein the aspect of are different from each other.

  According to this feature, the mixed state of the material gas can be changed between the center and the periphery of the first shower plate by changing the mode of the space formed by the gas flow path and the gas conduit. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the size of the gas conduit is different between the center and the peripheral edge.

  According to the said structure, the mixing state of material gas can be changed by the center and periphery of a 1st shower plate by changing the dimension of a gas conduit | pipe. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, the length of the gas conduit is preferably different between the center and the peripheral edge.

  According to the above configuration, the mixed state of the material gas can be changed between the center and the peripheral edge of the first shower plate by changing the length of the gas conduit. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that an outer diameter of the gas conduit is different between the center and the peripheral edge.

  According to the above configuration, the mixed state of the material gas can be changed between the center and the peripheral edge of the first shower plate by changing the outer diameter of the gas conduit. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that an inner diameter of the gas conduit is different between the center and the peripheral edge.

  According to the said structure, the mixing state of material gas can be changed with the center and periphery of a 1st shower plate by changing the internal diameter of a gas conduit | pipe. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the distance from the tip of the gas conduit to the substrate to be processed is different between the center and the periphery.

  According to the above configuration, the mixed state of the material gas can be changed between the center and the periphery of the first shower plate by changing the distance from the tip of the gas conduit to the substrate to be processed. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the size of the gas flow path is different between the center and the peripheral edge.

  According to the said structure, the mixed state of material gas can be changed with the center and periphery of a 1st shower plate by changing the dimension of a gas flow path. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the length of the gas flow path is different between the center and the peripheral edge.

  According to the above configuration, the mixed state of the material gas can be changed between the center and the periphery of the first shower plate by changing the length of the gas flow path. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that an inner diameter of the gas flow path is different between the center and the peripheral edge.

  According to the said structure, the mixing state of material gas can be changed with the center and periphery of a 1st shower plate by changing the internal diameter of a gas flow path. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the shape of the hole formed in the gas conduit is different between the center and the peripheral edge.

  According to the said structure, the mixing state of material gas can be changed with the center and periphery of a 1st shower plate by changing the aspect of the hole formed in a gas conduit. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, the hole is preferably formed at a tip of the gas conduit.

  According to the above configuration, since the plurality of holes are provided at the tip of the gas conduit serving as the flow path for the second gas, it is possible to further expand the ejection of the second gas (in the case of a pipe shape, a straight line). The mixing property of the first gas and the second gas is further improved, the gas concentration distribution on the surface of the substrate to be processed can be made uniform, and the controllability of the surface reaction of the substrate to be processed can be achieved. In other words, the film thickness and composition ratio can be improved, and the material utilization efficiency can be improved.

  In the vapor phase growth apparatus according to the present invention, the hole is preferably formed in a side wall of the gas conduit.

  According to the said structure, it becomes possible to change the area | region where gas mixes for every flow path by changing the hole position of a side wall. In addition, since the hole is provided in the side wall, the mixing of the first gas and the second gas can be further improved. Furthermore, by arranging the first gas conduit at the same height as the second gas conduit, the mixing area can be provided without changing the sectional area of the second gas conduit, so that the gas flow rate can be increased, A wide range of film forming conditions can be handled.

  In the vapor phase growth apparatus according to the present invention, the first shower plate is formed by an inner wall of the gas flow path in front of the tip of the gas conduit and mixes the first gas and the second gas. It is preferable that the volume of the mixing chamber is different between the center and the peripheral edge.

  According to the above configuration, the mixing state of the material gas can be changed between the center and the periphery of the first shower plate by changing the volume of the mixing chamber. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  In the vapor phase growth apparatus according to the present invention, the relative spatial positional relationship between the gas flow path and the gas conduit includes the center of the first shower plate, the peripheral edge of the first shower plate, and the It is preferable that they are different from each other in an intermediate region between the center and the peripheral edge.

  According to the above configuration, the mixing state can be changed more finely in the periphery of the shower plate, in the intermediate region, and in the central portion according to the film formation conditions, and the film formation rate and film quality of the substrate can be made more uniform.

  In the vapor phase growth apparatus according to the present invention, a first gas distribution space for supplying the first gas to the gas flow path is formed between the first shower plate and the second shower plate, and the second shower The plate is preferably detachably provided from the first shower plate so that the first gas distribution space is exposed.

  According to the above configuration, since the first gas distribution space can be exposed, the maintainability is improved, especially when an additive compound is generated inside the shower plate or when foreign matter is mixed. Cleanability is dramatically improved and internal contamination can be completely removed.

  In the vapor phase growth apparatus according to the present invention, the gas conduit has a flange fitted to the second shower plate, and the outer diameter of the flange of the gas conduit is smaller than the inner diameter of the gas flow path. Is preferred.

  According to the above configuration, the gas conduit can be exchanged from the reaction chamber side through the first shower plate without opening the gas distribution space.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the gas conduit is detachably provided on the second shower plate.

  According to the above configuration, the gas introduction pipe can be removed from the second shower plate, and the size of the mixing chamber can be changed by changing the length of the gas introduction pipe. By making the gas introduction pipe removable, it becomes possible to adjust the size of the mixing chamber only by changing the gas introduction pipe that becomes the flow path of the second gas, without having to remanufacture each main body. It can be set as the apparatus corresponding to the film-forming of various conditions. Further, even when the adduct compound adheres to the wall surface of the gas introduction pipe and the gas introduction pipe outlet is clogged, it is possible to replace only the clogged gas introduction pipe without cleaning the whole. Therefore, the maintenance time of the apparatus can be greatly shortened, and the operating rate of the apparatus can be improved.

  In the vapor phase growth apparatus according to the present invention, it is preferable that a refrigerant flow path for flowing a refrigerant for adjusting the temperature of the gas conduit is formed in the second shower plate.

  According to the above configuration, since the refrigerant flow path for adjusting the temperature of the second gas flow path is configured, the temperature of the second gas flow path can be varied, and the temperature of the second gas can be controlled. It becomes possible. That is, the temperature of the first gas and the second gas can be individually adjusted. Thereby, the controllability of the surface reaction of the substrate to be processed can be improved, that is, the film formation thickness and the composition ratio can be improved, and the material utilization efficiency can be improved.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the first gas includes a group III gas and the second gas includes a group V gas.

  According to the above configuration, the outlet of the gas introduction pipe serving as the flow path for the second gas receives heat from the heater directly and has a structure in which the temperature is likely to rise compared to the first gas flow path whose temperature is adjusted by the refrigerant flow path. It is. An organic gas is used as the group V gas, and unless the temperature is raised, molecules are decomposed and are not doped into the growth film, or are doped as molecules to form holes, leading to deterioration of film quality and growth rate. On the other hand, if the temperature of the substrate or the film formation chamber is too high, film formation on the wall surface of the film formation chamber other than the substrate, or molecules re-evaporate from the film formation substrate, resulting in a decrease in material efficiency, film quality, and film thickness. May cause non-uniformity. For this reason, the gas introduction pipe serving as the flow path for the second gas is set as a group V gas, heated in advance outside the reaction chamber, and the activated gas is supplied to the reaction chamber, thereby affecting the decomposition temperature of the group V gas. Therefore, the film formation quality and the substrate temperature can be set, and the film formation with high material efficiency is possible with the uniform film thickness and film quality.

  In the vapor phase growth apparatus according to the present invention, it is preferable to provide an elevating mechanism for moving the gas conduit and the gas flow path relatively up and down along the longitudinal direction of the gas conduit.

  According to the above configuration, the size of the mixing chamber of the first gas and the second gas can be varied, the material gas mixing property is improved, and the gas concentration distribution on the surface of the substrate to be processed is made uniform. Thus, the controllability of the surface reaction of the substrate to be processed can be improved, that is, the film formation thickness and the composition ratio can be improved, and the raw material utilization efficiency can be improved. In addition, the size of the mixing chamber can be varied during film formation, and even when growing a plurality of films in which the reaction gas flow rate and the substrate temperature to be processed are grown in one film formation, Since the optimum size of the mixing chamber can be set, an optimum single film can be laminated, and a high-quality multilayer film can be formed.

  In the vapor phase growth method according to the present invention, a first gas is supplied to the substrate to be processed by a first shower plate disposed to face a substrate holding member on which the substrate to be processed in the reaction furnace is placed. A vapor phase growth method for supplying a second gas toward the substrate to be processed by a second shower plate disposed on the opposite side of the substrate holding member with respect to the first shower plate, wherein the first shower plate Is formed with a gas flow path through which the first gas flows toward the substrate to be processed, and the second shower plate protrudes from the second shower plate and is inserted into the gas flow path. A gas conduit for flowing the second gas toward the substrate to be processed is formed by the gas flow path and the gas conduit at the center and the periphery of the first shower plate. Aspects between differentiated from each other and supplying toward said first and second gas to the substrate to be processed.

  According to this feature, the mixed state of the material gas can be changed between the center and the periphery of the first shower plate by changing the mode of the space formed by the gas flow path and the gas conduit. Therefore, the mixing state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  As described above, the vapor phase growth apparatus according to the present invention is different from each other in the form of the space formed by the gas flow path and the gas conduit at the center and the periphery of the first shower plate. The mixed state can be changed between the periphery and the center of the shower plate according to the film forming conditions, and the film forming rate and film quality of the substrate can be made uniform.

  An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a configuration of a vapor phase growth apparatus 1 according to the first embodiment. The vapor phase growth apparatus 1 is constituted by a vertical shower head type MOCVD apparatus. The vapor phase growth apparatus 1 includes a reaction furnace 14. In the reaction furnace 14, a disk-shaped substrate holding member 16 on which the substrate to be processed 15 is placed is provided. A shaft-like rotation transmission member 20 is coupled to the lower side of the substrate holding member 16, and the substrate is held so as to be rotatable around the rotation transmission member 20 perpendicular to the surface of the substrate to be processed 15 by a drive mechanism (not shown). A member 16 is provided. A heater 17 that heats the substrate holding member 16 is further provided below the substrate holding member 16.

  A gas supply portion 18 having a substantially cylindrical shape is provided on the upper side of the reaction furnace 14. The gas supply unit 18 includes a shower plate 2 and a shower plate 3. The shower plate 2 is disposed to face the substrate holding member 16 on which the substrate 15 to be processed in the reaction furnace 14 is placed, and is provided to supply the first gas toward the substrate 15 to be processed. The shower plate 3 is disposed on the opposite side of the substrate holding member 16 with respect to the shower plate 2 and is provided to supply the second gas toward the substrate 15 to be processed.

  FIG. 2 is a cross-sectional view showing a detailed structure of the gas supply unit 18 provided in the vapor phase growth apparatus 1, and FIG. 3 is an enlarged cross-sectional view of a part A shown in FIG. FIG. 4 is a plan view of the gas supply unit 18 provided in the vapor phase growth apparatus 1 as viewed from the substrate to be processed 15 side. FIG. 5 is a perspective view for explaining the shower plates 2 and 3 provided in the vapor phase growth apparatus 1.

  In the shower plate 2, a plurality of gas flow paths 4 a through which the first gas flows toward the substrate to be processed 15 are formed at predetermined intervals. The shower plate 2 has a wall surface 26 that faces the substrate holding member 16, and a channel outlet 25 of each gas channel 4 a is formed on the wall surface 26. A reaction chamber 19 is formed by the wall surface 26 and the inner wall of the reaction furnace 14. A gas discharge port 21 is formed at a position lower than the substrate holding member 16 on the side wall of the reaction furnace 14. An O-ring 22 a for sealing the reaction chamber 19 is provided between the reaction furnace 14 and the shower plate 2.

  A gas distribution space 9 is formed between the shower plate 2 and the shower plate 3 in order to supply the first gas to the gas flow path 4a. As shown in FIG. 5, the shower plate 3 is detachably provided from the shower plate 2 so that the gas distribution space 9 is exposed. Between the shower plate 2 and the shower plate 3, an O-ring 22b for sealing the gas distribution space 9 is provided. A plurality of gas inlets 23 for supplying the first gas to the gas distribution space 9 are provided at the periphery of the shower plate 2.

  The shower plate 3 has a plurality of gas conduits 5 provided to flow the second gas toward the substrate 15 to be processed, protruding from the shower plate 3 and inserted into the gas flow paths 4a. A gas flow path 4 b through which the second gas flows is formed in the gas conduit 5.

  The shower plate 3 has a base 7 and an upper plate 8. A gas distribution space 10 is formed between the base 7 and the upper plate 8. The upper plate 8 is detachably provided from the base 7 so that the gas distribution space 10 is exposed. An O-ring 22 c for sealing the gas distribution space 10 is provided between the base 7 and the upper plate 8. The upper plate 8 is formed with a second gas introduction port 24 for supplying the second gas to the gas distribution space 10.

  In the shower plate 2, a refrigerant flow path 11 for flowing a refrigerant for adjusting the temperature of the gas conduit 5 is formed around the gas flow path 4a.

  In the shower plate 2, a mixing chamber 12 in which the first gas and the second gas are mixed is formed by the inner wall of the gas flow path 4 a on the downstream side (front side) of the gas at the tip of the gas conduit 5.

FIG. 7 is a cross-sectional view showing the positional relationship between the gas flow path 4 a formed in the shower plate 2 and the gas conduit 5 provided in the shower plate 3. The gas channel 4 a and the gas conduit 5 shown on the left side indicate the positional relationship between the gas channel 4 a and the gas conduit 5 provided in the center of the shower plate 2. The gas flow path 4 a and the gas conduit 5 shown on the right side indicate the positional relationship between the gas flow path 4 a and the gas conduit 5 provided on the periphery of the shower plate 2. The protruding length of the gas conduit 5 is different between the center and the periphery of the shower plate 2, and the length of the peripheral gas conduit 5 is longer than the length of the central gas conduit 5.
Thus, the protruding length of the gas conduit 5 is adjusted to be shorter at the central portion so that the volume of the mixing chamber 12 is larger at the central portion than the peripheral portion of the shower plate 2. The protruding length of the gas conduit 5 may be adjusted as appropriate according to the film forming conditions.
In this way, even under conditions where the film formation rate increases from the center toward the periphery, the film formation rate at the center portion can be increased by increasing the mixing property of the first gas and the second gas at the center. The film thickness can be made uniform. Conversely, when the film formation rate decreases from the center toward the periphery, the parts at the center and the periphery may be reversed.
It should be noted that not only the gas introduction pipe 5 having two kinds of protruding lengths at the center part and the peripheral part of the shower plate 2 but also gas introduction pipes 5 having three or more kinds of protruding lengths may be used. good. For example, the relative spatial positional relationship between the gas flow path 4a and the gas conduit 5 is such that the center of the shower plate 2, the periphery of the shower plate 2, and the intermediate region between the center and the periphery are mutually You may comprise so that it may differ. Further, depending on the flow rate and the growth pressure, the film formation rate may be reduced in the vicinity of the peripheral portion. In that case, it is also conceivable to increase the protruding length of the peripheral edge.
As shown in FIG. 3 in which the mixing chamber 12 and the gas introduction pipe 5 are enlarged, the outer periphery of the opposite end of the flow outlet 27 of the gas conduit 5 is male threaded. A flange 40 is formed on the side of the flow outlet 27 of the male screw formed in the gas conduit 5.
The through hole 41 formed in the lower plate 34 a is subjected to female thread processing corresponding to the male thread of the gas conduit 5, and the counterbore hole 42 is formed to correspond to the flange 40. Thus, the gas conduit 5 can be fixed to the lower plate 34a by the screw structure. Furthermore, by providing the flange 40, it is possible to accurately define the protruding length D of the gas conduit 5. (Without the flange 40, the protruding length D changes according to the tightening condition of the screw. End up). Further, by inserting the flange 40 into the counterbore hole 42 of the lower plate 34a, no extra protrusion is generated in the gas distribution space 9, and the flow in the gas distribution space 9 is not disturbed. Further, since there is a possibility that the first gas and the second gas are diffused and mixed through the screw portion, a graphite sheet can be sandwiched between the screw portion and a sealing structure can be taken. In addition to the graphite sheet, a metal thin film sheet having corrosion resistance against a material gas such as a platinum thin film sheet can also be used. However, if the height of the flange 40 is a protrusion that does not disturb the flow in the gas distribution space 9, it is not essential to provide the counterbore hole 42.
According to the above configuration, the gas conduit 5 is configured to be removable (detachable) from the lower plate 34a, and the protruding length D of the gas conduit 5 can be easily changed. For this reason, it is possible to adjust the volume of the mixing chamber 12 in accordance with various film forming conditions such as a flow rate, a film forming temperature, and a growth pressure in accordance with a desired film forming rate and film quality. Further, the reaction purified product may adhere to the wall surface of the channel opening during film formation, and the channel outlet may be clogged, which may cause the film quality and the uniformity of the film thickness distribution and the film formation rate to decrease. However, if the structure is detachable, even if deposits are generated on the wall surface of the gas conduit 5 and the outlet of the flow path is clogged, only the clogged gas conduit 5a is replaced without washing the whole. Is possible. Therefore, the maintenance time of the apparatus can be greatly shortened, and the operating rate of the apparatus can be improved.
Even if the gas conduit 5 is not removable as described above, the effect of the present invention can be obtained by adjusting the volume of the mixing chamber 12. In this case, a large number of through holes are arranged in the lower plate (base 7) of the second gas flow path. The plurality of gas conduits 5 are joined by vacuum brazing, electron beam welding, TIG welding, diffusion joining, or the like so as to keep airtightness. The gas conduit 5 may be formed directly on the second gas flow path lower plate (base 7) by cutting or the like. However, as described above, it is preferable to adopt a detachable configuration when dealing with various film forming conditions and considering maintainability.

FIGS. 8 (a), (b), (c), FIGS. 9 (a), (b), and FIGS. 10 (a) and 10 (b) show the gas flow path 4a formed in the first shower plate 2 and the second shower plate. 3 is a cross-sectional view showing another relationship with the gas conduit 5 provided in FIG. The example shown in FIG. 7 shows an example in which the length of the gas conduit 5 is different between the center and the periphery. However, the present invention is not limited to this. For example, as shown in FIG. 8A, the inner diameter d of the gas conduit 5 may be increased at the center and decreased at the periphery. With this configuration, the flow rate of the second gas at the periphery is smaller than the flow rate of the second gas at the center. For this reason, the distribution of film thickness and composition ratio can be adjusted to be uniform according to conditions such as flow rate. For example, in the case of forming an AlGaAs film, TMG and TMA are used as the source gas for the first gas, and AsH ₃ is used as the source gas for the second gas, so that the V / III ratio is reduced (the AsH ₃ gas is reduced). When the film formation rate is lowered at the periphery, the growth rate can be increased and the film thickness uniformity is increased by reducing the amount of AsH ₃ introduced at the periphery. In addition, when the V / III ratio is small (the amount of AsH ₃ introduced is small), it is easier for Ga to enter than Al, so the inner diameter of the inner tube can be reduced at the periphery to increase the Ga composition ratio. The composition ratio can also be adjusted as appropriate.

Further, as shown in FIG. 8B, the outer diameter e of the gas conduit 5 may be configured to be small at the center and large at the periphery. With this configuration, the flow rate of the first gas at the periphery is less than the flow rate of the first gas at the center. It is also conceivable to reverse the center and peripheral parts according to the flow rate and other conditions. According to this configuration, the distribution of film thickness and composition ratio can be adjusted to be uniform according to conditions such as flow rate. For example, in the case of AlGaAs film formation, TMG and TMA, which are Group III gases, are used as the source gas for the first gas, and AsH ₃ which is a Group V gas is used as the source gas for the second gas. Since the film is often formed under conditions determined by the amount of Group III gas introduced, when film formation is performed under the condition that the film formation rate is slow at the central part, the amount of Group III gas introduced at the central part is large, and the periphery By reducing the thickness, the film thickness can be made uniform. Further, since the V / III ratio can be changed between the central portion and the peripheral portion, the composition ratio can also be adjusted as appropriate. Depending on the conditions such as the flow rate, it is also conceivable to reverse the parts at the center and the periphery.
Further, as shown in FIG. 8 (c), a hole formed in the gas conduit 5 is formed at the tip of the gas conduit 5 at the center, at the peripheral edge, at the side wall of the gas conduit 5, and at the peripheral edge, the gas conduit 5 is formed. You may comprise so that the front-end | tip of 5 may be extended to the front-end | tip of the gas flow path 4a. With this configuration, the flow rate of the introduced gas at the periphery is smaller than the flow rate of the introduced gas at the center. In the case of a film formation condition with a slow film formation rate at the center, the film thickness can be made uniform by reducing the flow rate of introduced gas at the periphery and slowing down the film formation rate. If the film formation rate is high at the center, the parts at the center and the periphery may be reversed.

Further, as shown in FIG. 9 (a), the hole 6c is formed at a position away from the tip of the gas conduit 5 at the center, and the tip of the gas conduit 5 is formed at the peripheral edge. The hole 6d may be formed at a position close to. With this configuration, the region where the first gas and the second gas are mixed is larger in the center than in the periphery, and the same effect as the configuration shown in FIG. 7 is achieved.
As shown in FIG. 9B, the size of the hole formed in the side wall of the gas conduit 5 may be changed between the center and the periphery. Specifically, a large hole 6 e may be formed in the side wall of the central gas conduit 5, and a small hole 6 f may be formed in the side wall of the peripheral gas conduit 5. With this configuration, the flow rate of the second gas is smaller at the periphery than at the center, and the same effect as the configuration shown in FIG.

Moreover, as shown to Fig.10 (a), you may vary the magnitude | size of the hole formed in the front-end | tip of the gas conduit 5 with a center and a periphery. Specifically, a large hole 6g is formed at the tip of the central gas conduit 5, a small hole 6h is formed at the tip of the peripheral gas conduit 5, and the protruding length of the peripheral gas conduit 5 is set to the center gas. You may comprise shorter than the protrusion length of the conduit | pipe 5. FIG. With this configuration, the flow rate of the second gas is smaller at the periphery than at the center, and the same effect as the configuration shown in FIG.
As shown in FIG. 10 (b), the mode of the holes formed in the gas conduit 5 may be different between the center and the periphery. Specifically, a hole is formed in the tip of the gas conduit 5 at the center, and a hole is formed in the side wall of the gas conduit 5 at the periphery, and the hole is formed from the inside of the gas conduit 5 toward the outside. You may form along the diagonal direction which approaches a front-end | tip. With this configuration, the flow rate of the introduced gas at the periphery is smaller than the flow rate of the introduced gas at the center, and the same effect as the configuration shown in FIG.

  In addition, you may comprise so that the distance from the gas outflow port (front-end | tip) in the gas conduit 5 to the to-be-processed substrate 15 may mutually differ in the center and periphery of a shower plate.

  The shower plate 2 includes a lower plate 29 provided facing the substrate holding member 16, an upper plate 28 provided on the opposite side of the substrate holding member 16 at a predetermined interval from the lower plate 29, and a lower plate 29. And a gas conduit 30 provided through the upper plate 28 to form the gas flow path 4a.

  The shower plate 2 is provided with a flange portion 32 in which a first gas introduction port 23 for introducing the first gas and an introduction path 31 for guiding the first gas to the gas distribution space 9 are formed. The base 7 and the upper plate 8 are fixed to the flange portion 32 with fixing screws 39 at the periphery.

  The refrigerant flow path 11 is provided with a refrigerant adjustment ring 33 for evenly supplying the refrigerant around each gas flow path 4a. The gas distribution space 9 is provided with a first gas adjustment ring 36 for uniformly supplying the first gas to the gas flow paths 4a. The gas distribution space 10 is provided with a second gas adjusting ring 35 for enabling the second gas to be supplied uniformly to the gas conduits 5.

  As described above, in the vapor phase growth apparatus 1, the inside of the vapor deposition apparatus 1 is isolated from the atmosphere side, the reaction furnace 14 that maintains an airtight state, the substrate holding member 16 that places the substrate 15 to be processed, and the substrate 15 to be processed are heated. The reaction chamber includes a substrate heater 17 that performs the above operation and a gas supply unit 18 that is provided at a position facing the substrate holding member 16 and has a plurality of gas flow path outlets that supply a plurality of source gases toward the substrate 15 to be processed. 19 is constituted.

  The substrate holding member 16 is provided at one end of the rotation transmission member 20, and the rotation transmission member 20 can be rotated by a rotation mechanism (not shown).

  When forming a thin film on the main surface of the substrate 15 to be processed, a source gas (hereinafter simply referred to as a gas) is introduced from the gas supply unit 18 into the reaction chamber 19. At this time, the processing substrate 15 is heated by the heater 17 through the substrate holding member 16, and a film forming chemical reaction on the processing substrate 15 is promoted, whereby a thin film is formed on the processing substrate 15. The The gas that has passed over the substrate to be processed 15 is discharged from the gas discharge port 21.

  Next, the structure of the gas supply unit 18 will be described more specifically. In FIG. 1, the gas supply unit 18 is sealed so as to maintain an airtight state by a reaction furnace 14 and an O-ring 22a, and the gas supply unit 18 and the reaction furnace 14 are configured to be removable. Yes.

  The gas supply unit 18 is provided with a first gas introduction port 23 and a second gas introduction port 24, and different source gases are supplied to the gas supply unit 18.

  The first gas and the second gas are separated, and a plurality of shower plate-shaped gas flow paths (first gas flow path 4a, second gas flow) for independently discharging each gas into the gas distribution space 9 and the gas distribution space 10. Gas passage 4b), the second gas passage 4b is disposed (concentrically) in each first gas passage 4a, and the first gas passage outlet 25 is connected to the reactor. The second gas flow path outlet 27 formed on the wall surface 26 is configured and arranged on the gas supply source side (that is, the side farther from the substrate 15 to be processed) than the first gas flow path outlet 25. The refrigerant flow path 11 that constitutes the mixing chamber 12 of each first gas and the second gas, and adjusts the temperature of the first gas flow path 4a between the first gas flow path 4a and the reaction furnace wall surface 26 is provided. Composed.

  The upper plate 28 of the first gas flow path and the lower plate 29 of the first gas flow path are formed with a number of through-holes and arranged at a distance A, and the gas conduit 30 serving as the gas flow path 4a. However, it is joined to the through hole by vacuum brazing, electron beam welding, TIG welding, diffusion bonding or the like so as to keep hermeticity. FIG. 3 shows a shape in which both ends of the gas conduit 30 are joined to the upper plate 28 of the first gas flow path and the lower plate 29 of the first gas flow path, respectively, but the present invention is limited to this. Not. The gas conduit 30 may be formed directly on the upper plate 28 or the lower plate 29 by cutting or the like.

  By comprising as mentioned above, the refrigerant | coolant flow path 11 which can adjust the temperature of the gas flow path 4a is formed.

  Furthermore, the flange part of the 1st gas flow path which formed the 1st gas introduction flow path 31 and the refrigerant | coolant flow path 11 in the member comprised by the upper plate 28, the lower plate 29, and the gas conduit 30 of the 1st gas flow path. 32 are joined. Although the flange portion 32 is a separate body here, the flange portion 32 may be formed on either or both of the upper plate 28 and the lower plate 29. As a joining method, any method such as vacuum brazing, electron beam welding, TIG welding, and diffusion joining may be used.

  In addition, a refrigerant adjustment ring 33 is provided in the refrigerant flow path 11 so that the refrigerant can be supplied uniformly. A plurality of holes are formed in the refrigerant adjustment ring 33 so that the refrigerant can be supplied uniformly. The diameter of each hole is appropriately adjusted so that the refrigerant can be supplied uniformly. The shape may be circular, rectangular, or polygonal.

  The member configured as described above is referred to as a shower plate 2.

  The lower plate (base 7) of the second gas flow path is provided with a number of through holes, and the plurality of gas conduits 5 are maintained by vacuum brazing, electron beam welding, TIG welding, diffusion bonding, etc. so as to keep airtightness. It is joined. FIG. 3 shows a shape in which the gas conduit 5 is joined to the second gas flow path lower plate (base 7), but the present invention is not limited to this. The gas conduit 5 may be formed directly on the second gas flow path lower plate (base 7) by cutting or the like.

  The base 7 and the upper plate 8 are disposed at a distance B, and are sealed with a fixing screw 39 in an detachable state by an O-ring 22c. By configuring as described above, the gas distribution space 10 is formed. In addition, an adjustment ring 35 is disposed in the gas distribution space 10, and the adjustment ring 35 has a plurality of holes for enabling the second gas to be supplied uniformly. The diameter of each hole is appropriately adjusted so that the second gas can be supplied uniformly. The shape may be circular, rectangular, or polygonal.

  The member configured as described above is called a shower plate 3.

  A shower plate 3 is installed on the shower plate 2 to form a gas distribution space 9 having a distance c. The shower plate 2 and the shower plate 3 are fixed by an O-ring 22c so as to be kept airtight.

  An adjustment ring 36 is disposed in the gas distribution space 9, and the adjustment ring 36 has a plurality of holes for allowing the first gas to be supplied uniformly. The diameter of each hole is appropriately adjusted so that the first gas can be supplied uniformly. The shape may be circular, rectangular, or polygonal.

  The gas flow path outlet 27 of the gas flow path 4b concentrically enclosed in the gas flow path 4a is formed at a distance L from the gas flow path outlet 25. By comprising in this way, the mixing chamber 12 of 1st gas and 2nd gas is formed in the gas flow path 4a.

  By configuring as described above, the mixing property of the reaction gas is improved, the gas concentration distribution on the surface of the substrate to be processed can be made uniform, and the controllability of the surface reaction of the substrate to be processed is improved. While improving a film thickness and a composition ratio, raw material utilization efficiency can be improved.

  In addition, since the coolant channel 11 is configured, it is possible to prevent the addition compound from being generated before reaching the substrate to be processed.

  In the present embodiment, the shower plate 3 is sealed by the O-ring 22b and can be removed, so that the first gas distribution space 9 can be exposed. With the above configuration, maintainability is improved. In particular, even when an additive compound is generated inside the gas shower plate 2 or when foreign substances are mixed in, the cleaning property is dramatically improved and internal contamination is completely removed. it can. According to the structure described in the conventional patent document 2, since it is joined by brazing or the like, the inside cannot be completely cleaned. Since the hole is small (φ0.5 mm), the cleaning liquid is difficult to flow sufficiently, and stagnation can occur, there is a high possibility that foreign matter will accumulate.

  In the present embodiment, the configuration example in which the shower plate 3 is sealed by the O-ring 22b and is removable is shown, but the present invention is not limited to this. The shower plate 3 may be configured to be removable from the shower plate 2 by other mechanisms.

  As another configuration, the shower plate 3 can be configured to be removable from the shower plate 2 by a “knife edge type metal seal flange” (also referred to as an ICF flange or a conflat flange). Generally, it can be configured to be removable by a vacuum sealable flange type.

  "Knife edge type metal seal flange" was developed by Varian as a flange for ultra-high vacuum and used like a standard flange for ultra-high vacuum. In Japan, the Japan Vacuum Association uses JVIS003 "Vacuum flange shape and dimensions for vacuum equipment" as the name of "Knife-edge type metal seal flange" and the dimensional drawing is described as a reference drawing. On the other hand, the ISO standard is currently being established, and the ISO / CD3669 baked flange is being studied at the draft stage.

  The bakable flange that is going to be standardized by ISO includes other types of seal mechanisms such as knife-edge type, hollow metal “O” ring type, metal “C” ring, etc. We are trying to standardize dimensions.

  The knife-edge type metal seal flange is a joint made of all metal with a pointed edge on the inside and usually sealed by plastic deformation with a copper gasket interposed therebetween. The configuration of such a knife edge type metal seal flange is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-294146.

  Further, the upper plate 8 of the shower plate 3 is sealed by an O-ring 22c and can be removed, so that the gas distribution space 10 can be exposed. According to the above configuration, since the gas distribution space 10 can be exposed, the maintainability is improved. In particular, when an additive compound is generated in the gas distribution space 10 and the gas flow path 4b, foreign substances are mixed in. Even in such a case, the detergency is greatly improved and internal contamination can be completely removed.

  In the present embodiment, the upper plate 8 of the shower plate 3 is sealed by the O-ring 22c and can be removed. However, the present invention is not limited to this. The upper plate 8 may be configured to be removable from the base 7 by another mechanism. For example, the upper plate 8 can be configured to be removable from the base 7 by the above-described “knife edge type metal seal flange”.

  Moreover, in this Embodiment, although the gas distribution space 9 and 10 showed the structure provided in the upper side of the reaction chamber 19, this invention is not limited to this. Conversely, the apparatus may be configured upside down so that the reaction chamber is on the upper side and the shower is blown up from the gas distribution space side on the lower side. The same applies to other embodiments described later.

Moreover, in this Embodiment, the front-end | tip of the gas conduit 5 is inserted in the middle of the gas flow path 4a, and the mixing chamber 12 is formed by the inner wall of the gas flow path 4a ahead of the front-end | tip of the gas conduit 5. However, the present invention is not limited to this. The tip of the gas conduit 5 and the wall surface 26 may be configured to be on the same plane, or the tip of the gas conduit 5 may be configured to protrude from the wall surface 26 toward the substrate 15 to be processed. In these cases, the mixing chamber 12 is not formed. The same applies to other embodiments described later.
Film formation experiments were performed using the vapor phase growth apparatus (MOCVD apparatus) 1 manufactured with such a configuration. The shower plates 2 and 3 have a substantially disk shape, and about 2400 nozzles are arranged on a grid having a pitch of 7.5 mm. Further, the outlet of the gas conduit 5 has a nozzle diameter of φ1.5 mm, and the outlet 25 of the mixing chamber 12 has a nozzle diameter of φ4.0 mm. The protruding length D is about 300 nozzles in the central portion of the shower plate 2, and the protruding length D of the gas conduit 5 is 15 mm shorter than the other peripheral portions, and the height L of the mixing chamber is the central portion. About 300 nozzles were 20 mm, and other peripheral portions were 5 mm. From this, the volume of the mixing chamber 12 is larger in the central portion than in the peripheral portion. Nineteen 4-inch substrates were arranged in the same range as the nozzle portion as the substrate for film formation. The material gas used was adjusted so that Group III TMG was introduced at a flow rate of 10 sccm (Standard cc / min) and AsH ₃ was introduced into Group V at a flow rate of 60 sccm. In addition, hydrogen at a flow rate of 260 slm (Standard liter / min) as a carrier gas was introduced into the Group III and Group V in the same amount mixed with the material gas to form a GaAs crystal on the GaAs substrate.
The distribution of the film formation rate at this time is shown in FIG. FIG. 11 shows a case where the curve C1 is in this embodiment and the size of the mixing chamber 12 is adjusted at the center and the periphery of the shower plate, and the curve C2 is adjusted at the center and the periphery of the shower chamber 12. It is the graph in the case of the conventional (the mixing chamber 12 is the same) which has not been carried out. The horizontal axis represents the distance from the center of the shower plate, and the vertical axis represents the GaAs growth rate. Conventionally (curve C2 in the figure), the growth rate is small at the center portion of the shower plate, and the growth rate tends to increase as it approaches the periphery along the radial direction. On the other hand, by enlarging the mixing chamber 12 at the center portion of the shower plate (curve C1 in the figure), the film formation rate at the center portion is increased and the uniformity is improved.

(Embodiment 2)
FIG. 12 is a cross-sectional view showing the configuration of the vapor phase growth apparatus 1a according to the second embodiment. The same components as those described above are denoted by the same reference numerals. Therefore, detailed description of these components is omitted.

  The difference from the vapor phase growth apparatus 1 of the first embodiment described above is that an elevating mechanism 13 is provided between the shower plate 2 and the shower plate 3. The elevating mechanism 13 is constituted by a bellows. “Bellows” refers to a tube made of metal provided with pleats to provide elasticity, airtightness, and springiness. In other words, it can be said that the “bellows” is a “expandable tube”.

  The elevating mechanism 13 is formed in the longitudinal direction of the gas conduit 5 in order to adjust the volume of the mixing chamber 12 formed by the tip of the gas conduit 5 and the gas flow path 4a and in which the first gas and the second gas are mixed. It is comprised so that the gas conduit 5 and the gas flow path 4a may be raised-lowered along. Although FIG. 12 shows an example in which the lifting mechanism 13 moves the shower plate 2 and the shower plate 3 relatively up and down along the longitudinal direction of the gas conduit 5, the present invention is not limited to this. The elevating mechanism 13 may be configured to move the gas conduit 5 and the shower plate 3 relatively up and down along the longitudinal direction of the gas conduit 5.

  Thus, the shower plate 2 and the shower plate 3 can be joined via the lifting mechanism 13. According to the above configuration, the position of the shower plate 3 can be changed using the bending of the bellows of the lifting mechanism 13. It is also possible to drive automatically by a drive mechanism (not shown).

  According to the above configuration, the size of the mixing chamber 12 can be changed, the raw material gas mixing property can be improved, and the gas concentration distribution on the surface of the substrate to be processed 15 can be made uniform. The controllability of 15 surface reactions can be improved. That is, the film forming thickness and the composition ratio can be improved, and the raw material utilization efficiency can be improved. In addition, the size of the mixing chamber 12 can be varied during film formation. For this reason, even when growing a plurality of films in which the reaction gas flow rate and the temperature of the substrate 15 to be processed are grown in a single film formation, the optimum size of the mixing chamber 12 can be set for each condition. As a result, an optimal single film can be laminated, and a high-quality multilayer film can be formed.

  Furthermore, by the relative position movement of the gas conduit 5 and the gas flow path 4a, the degree of protrusion of the gas conduit 5 from the gas flow path 4a, the distance from the tip of the gas conduit 5 to the substrate 15 to be processed, the gas flow path 4a Since the distance from the exit can be changed, the film quality and growth rate can be changed.

  By installing a bellows (elevating mechanism 13) by welding or flange connection between the top surface of the shower plate 2 and the bottom surface of the shower plate 3, the gas distribution space 9 is isolated from the outside (atmosphere), and the interior Can be kept airtight, and the height position of the shower plate 3 can be adjusted using the bending of the bellows (elevating mechanism 13). The height position of the shower plate 3 can be driven by various methods such as a ball screw, an air cylinder, and a height adjustment bolt.

(Embodiment 3)
FIG. 13 is an enlarged cross-sectional view illustrating a configuration of a gas supply unit provided in the vapor phase growth apparatus according to the third embodiment. The outer periphery of the gas conduit 5a opposite to the flow path outlet 27a is provided with a male thread. A flange 40 is formed on the side of the flow outlet 27a of the male screw formed in the gas conduit 5a.

  The through hole 41 formed in the lower plate 42 is subjected to a female thread process corresponding to the male thread of the gas conduit 5 a, and the counterbore hole 42 is formed so as to correspond to the flange 40. Thus, the gas conduit 5a can be fixed to the lower plate 42 by the screw structure. Furthermore, by providing the flange 40, it is possible to accurately define the protruding length D of the gas conduit 5a (without the flange 40, the protruding length D changes according to the tightening condition of the screw. End up). Further, by inserting the flange 40 into the counterbore hole 42 of the lower plate 34a, no extra protrusion is generated in the gas distribution space 9, and the flow in the gas distribution space 9 is not disturbed. Further, since there is a possibility that the first gas and the second gas are diffused and mixed through the screw portion, a graphite sheet can be sandwiched between the screw portion and a sealing structure can be taken. In addition to the graphite sheet, a metal thin film sheet having corrosion resistance against a raw material gas such as a platinum thin film sheet can also be used.

  However, if the height of the flange 40 is a protrusion that does not disturb the flow in the gas distribution space 9, it is not essential to provide the counterbore 42.

  According to the above configuration, the gas conduit 5a is configured to be removable (detachable) from the lower plate 34a, and the size of the mixing chamber 12 can be changed by changing the protruding length D of the gas conduit 5a. Is possible. The position of the gas conduit 5a can be changed also by the method described in the second embodiment. However, since the size of the gas distribution space 9 is variable, depending on the conditions, the reaction gas can be supplied from a uniform shower plate. May not be possible (when the gas distribution space 9 is extremely narrow). In such a case, since the gas conduit 5a can be removed, it is not necessary to remanufacture the main body, and adjustment can be made only by changing the gas conduit 5a. Device.

  Moreover, according to the said structure, the change of the diameter of the 2nd gas flow path exit 27 becomes easy. For example, when the film thickness of the substrate to be processed 15 on the outer peripheral side among the plurality of substrates to be processed 15 installed on the substrate holding member 16 is different from that in the central portion, the temperature on the substrate holding member 16 is usually set. By changing the distribution (increasing or decreasing the temperature of the substrate 15 to be processed arranged on the outer peripheral side) and changing the temperature of the gas phase, a uniform film is formed. However, when the temperature is changed, the film forming composition is also changed. Therefore, it is conceivable to adjust the flow rate of the reaction gas supplied to the substrate 15 to be processed. However, in the case of the shower plate method, changing the flow rate changes the overall flow rate. For each flow rate adjustment, it was necessary to recreate the shower plate with different hole diameters.

  However, the gas flow path 4b having various hole diameters can be easily formed by removing and replacing the gas conduit 5a. In addition, by changing the outer diameter of the gas flow path outlet 27a, that is, the outer diameter of the gas conduit 5a, the cross-sectional area of the gas flow path 4a can be changed, and fine flow rate adjustment can be performed for each area. is there. From the above, it is possible to provide a vapor phase growth apparatus that supports film formation under various conditions.

  In addition, even when an additional compound is generated in a part of the gas flow path 4b, and the additional compound adheres to the wall surface in the gas flow path 4b and the flow path outlet 27a is clogged, the whole is clogged without washing. It is possible to exchange only the gas flow path 4b (gas conduit 5a) at the location. Therefore, the maintenance time of the apparatus can be greatly shortened, and the operating rate of the apparatus can be improved.

  In the present embodiment, an example in which a screw is formed on the gas conduit 5a so as to be removable (detachable) from the lower plate 34a has been shown. However, the present invention is not limited to this. The gas conduit 5a may be detachable (detachable) from the lower plate 34a by another mechanism.

Further, when the mixing chamber 12 is formed, not only the size of the mixing chamber 12 can be adjusted, but also the following adjustment is possible. For example, if the gas conduit 5a has the same length, the size of the space (mixing chamber 12) in front of the tip is the same, but a gas cylinder type gas conduit (gas conduit 5a) having an open front end as shown in FIG. Even so, according to the difference in the inner diameter, the state in which the gas is mixed (the degree of mixing, the speed of flowing out from the outlet, the outflow direction, etc.) can be variously adjusted. Further, in the type having an opening in the closed surface of the tip as shown in FIG. 13A, the gas is mixed (the degree of mixing, the speed of flowing out from the outlet) according to the arrangement, size and number of the openings. , Outflow direction, etc.) can be adjusted in various ways. Also, depending on whether the direction of gas pipe ejection is the direction of ejection from the end face as shown in FIG. 13 (a) or the direction of ejection from the side face as shown in FIG. 13 (b), The state in which the gas is mixed (the degree of mixing, the speed at which the gas flows out from the outlet, the outflow direction, etc.) can be variously adjusted. Further, the gas conduit of the type shown in FIG. 13 (a) in which an opening is formed on the closed surface of the distal end depends on whether it opens perpendicularly or obliquely with respect to the closed surface of the distal end. The state in which the gas is mixed (the degree of mixing, the speed at which the gas flows out from the outlet, the flow direction, etc.) can be variously adjusted.
FIG. 13A is a perspective view showing the configuration of a gas conduit 5a provided in the gas supply section of the vapor phase growth apparatus, and FIG. 13B is a perspective view showing the configuration of another gas conduit 5b. According to the configuration shown in FIG. 13A, it is possible to further widen the ejection of the second gas by forming a plurality of holes 6 at the outlet of the gas conduit 5a (in the case of a pipe shape, a straight line). The second gas outflow velocity from each hole 6 is increased as compared with the conventional case, and fine injection with a narrow pitch can be realized. For this reason, the turbulence of the second gas that flows out increases, and the miscibility with the first gas is further improved. Further, the gas concentration distribution on the surface of the substrate to be processed can be made uniform, and the controllability of the surface reaction of the substrate to be processed can be improved, that is, the film thickness and composition ratio can be improved, and the raw material utilization efficiency can be improved. be able to.

  According to the configuration of FIG. 13B, a plurality of holes 6 are formed in the side surface of the gas conduit 5b, thereby ejecting the second gas into the first gas flow path in the side surface direction. Since the second gas outflow rate from each hole 6 is increased as compared with the prior art and is ejected to the first gas flow path, the mixing property of the outflowed second gas and the first gas is further improved.

  In the present invention, it is needless to say that the shapes of the reaction furnace, shower plate and other members constituting the MOCVD apparatus are not limited to the shapes shown in FIG.

  In the above-described first to third embodiments, group III gas can be used as the first gas and group V gas can be used as the source gas as the second gas.

  In the present invention, examples of the group III element include Ga (gallium), Al (aluminum), and In (indium). Examples of the group III gas containing the group III element include trimethylgallium (TMG). ) Or one or more organic metal gases such as trimethylaluminum (TMA) can be used.

Examples of the group V element include N (nitrogen), P (phosphorus), and As (arsenic). Examples of the group V gas containing the group V element include ammonia (NH ₃ ), phosphine (PH ₃ ). ) Or one or more hydrogen compound gases such as arsine (AsH ₃ ) can be used.

  According to the above configuration, the second gas flow path outlet 27 directly receives heat from the heater, and has a structure in which the temperature rises more easily than the first gas flow path 4 a whose temperature is adjusted by the refrigerant flow path 11. An organic gas is used as the group V gas. Unless the temperature is increased, molecules are decomposed and are not doped into the growth film, or are doped as molecules to form holes, leading to deterioration in film quality and growth rate. Therefore, by setting the second gas flow path 4b to be a group V gas, the temperature of the substrate to be processed 15 is increased by supplying the activated gas to the reaction furnace 14 in advance by heating it outside the reaction furnace 14. It is possible to proceed the gas phase reaction while maintaining a temperature at which the Group III gas is not thermally decomposed.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention relates to a vapor phase growth comprising a shower plate disposed to face a substrate holding member for placing a substrate to be processed in a reaction furnace and provided to supply gas toward the substrate to be processed. The present invention can be applied to an apparatus and a vapor deposition method.

1 is a cross-sectional view showing a configuration of a vapor phase growth apparatus according to a first embodiment. It is sectional drawing which shows the detailed structure of the gas supply part provided in the said vapor phase growth apparatus. It is an expanded sectional view of the A section shown in FIG. It is the top view which looked at the gas supply part provided in the said vapor phase growth apparatus from the to-be-processed substrate side. It is a perspective view for demonstrating the 1st and 2nd shower plate provided in the said vapor phase growth apparatus. It is a perspective view for demonstrating the said 2nd shower plate. It is sectional drawing which shows the relationship between the gas flow path formed in the said 1st shower plate, and the gas conduit | pipe provided in the said 2nd shower plate. (A) (b) (c) is sectional drawing which shows the other relationship between the gas flow path formed in the said 1st shower plate, and the gas conduit | pipe provided in the said 2nd shower plate. (A) (b) is sectional drawing which shows the further another relationship between the gas flow path formed in the said 1st shower plate, and the gas conduit | pipe provided in the said 2nd shower plate. (A) (b) is sectional drawing which shows the further another relationship between the gas flow path formed in the said 1st shower plate, and the gas conduit | pipe provided in the said 2nd shower plate. It is a graph which shows the relationship between the GaAs growth rate by the said vapor phase growth apparatus, and the distance from the center of a shower plate. FIG. 3 is a cross-sectional view showing a configuration of a vapor phase growth apparatus according to a second embodiment. It is an expanded sectional view which shows the structure of the gas supply part of the vapor phase growth apparatus which concerns on Embodiment 3, (a) is a perspective view which shows the structure of the gas conduit | pipe provided in the gas supply part of the said vapor phase growth apparatus. (B) is a perspective view showing the configuration of another gas conduit. It is sectional drawing which shows the structure of the conventional vapor phase growth apparatus typically.

Explanation of symbols

1 Vapor growth equipment 2 Shower plate (first shower plate)
3 Shower plate (second shower plate)
4a, 4b Gas flow path 5 Gas conduit 6 Hole 7 Base 8 Upper plate (cover plate)
9 Gas distribution space (first gas distribution space)
10 Gas distribution space (second gas distribution space)
DESCRIPTION OF SYMBOLS 11 Refrigerant flow path 12 Mixing chamber 13 Elevating mechanism 14 Reaction furnace 15 Substrate 16 Substrate holding member 40 Flange

Claims (21)

A first shower plate that is disposed to face a substrate holding member on which a substrate to be processed in the reaction furnace is placed and supplies a first gas toward the substrate to be processed;
A vapor phase growth apparatus comprising: a second shower plate disposed on an opposite side of the substrate holding member to the first shower plate and supplying a second gas toward the substrate to be processed;
The first shower plate has a gas flow path through which the first gas flows toward the substrate to be processed.
The second shower plate has a gas conduit that protrudes from the second shower plate and is inserted into the gas flow path to flow the second gas toward the substrate to be processed.
The vapor phase growth apparatus characterized in that the space formed by the gas flow path and the gas conduit is different between the center and the periphery of the first shower plate.   The vapor phase growth apparatus according to claim 1, wherein dimensions of the gas conduit are different from each other at the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein the gas conduits have different lengths at the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein an outer diameter of the gas conduit is different between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein an inner diameter of the gas conduit is different between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein the distance from the tip of the gas conduit to the substrate to be processed is different between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein dimensions of the gas flow path are different from each other between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein the length of the gas flow path is different between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein an inner diameter of the gas flow path is different between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 1, wherein the holes formed in the gas conduit are different from each other between the center and the peripheral edge.   The vapor phase growth apparatus according to claim 10, wherein the hole is formed at a tip of the gas conduit.   The vapor phase growth apparatus according to claim 10, wherein the hole is formed in a side wall of the gas conduit. The first shower plate has a mixing chamber that is formed by an inner wall of the gas flow path in front of the tip of the gas conduit and mixes the first gas and the second gas.
The vapor phase growth apparatus according to claim 1, wherein the volume of the mixing chamber is different between the center and the peripheral edge.   The relative spatial positional relationship between the gas flow path and the gas conduit includes the center of the first shower plate, the peripheral edge of the first shower plate, and an intermediate region between the central and peripheral edge. The vapor phase growth apparatus according to claim 1, which are different from each other. A first gas distribution space for supplying the first gas to the gas flow path is formed between the first shower plate and the second shower plate;
2. The vapor phase growth apparatus according to claim 1, wherein the second shower plate is detachably provided from the first shower plate so that the first gas distribution space is exposed. The gas conduit has a flange mating with the second shower plate;
The vapor phase growth apparatus according to claim 1, wherein an outer diameter of the flange of the gas conduit is smaller than an inner diameter of the gas flow path.   The vapor deposition apparatus according to claim 1, wherein the gas conduit is detachably provided on the second shower plate.   The vapor phase growth apparatus according to claim 1, wherein a refrigerant flow path for flowing a refrigerant for adjusting the temperature of the gas conduit is formed in the second shower plate. The first gas includes a group III gas,
The vapor phase growth apparatus according to claim 1, wherein the second gas includes a group V gas.   The vapor phase growth apparatus according to claim 1, further comprising an elevating mechanism for moving the gas conduit and the gas flow path relatively up and down along a longitudinal direction of the gas conduit. Supplying a first gas toward the substrate to be processed by a first shower plate disposed facing a substrate holding member on which the substrate to be processed in the reaction furnace is placed;
A vapor phase growth method for supplying a second gas toward the substrate to be processed by a second shower plate disposed on the opposite side of the substrate holding member with respect to the first shower plate,
The first shower plate has a gas flow path through which the first gas flows toward the substrate to be processed.
The second shower plate has a gas conduit that protrudes from the second shower plate and is inserted into the gas flow path to flow the second gas toward the substrate to be processed.
The first and second gases are supplied toward the substrate to be processed by changing the form of the space formed by the gas flow path and the gas conduit at the center and the periphery of the first shower plate. The vapor phase growth method characterized by the above-mentioned.

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