JP4865672B2 - Vapor phase growth apparatus and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a vapor phase growth apparatus such as a vertical showerhead type MOCVD (Metal Organic Chemical Vapor Deposition), and a method for manufacturing a semiconductor element.

  Conventionally, in devices such as light-emitting diodes and semiconductor lasers, thin films of III-V group semiconductor crystals such as GaAs and InGaP have been used. Recently, InGaN and InGaNAs called III-V nitrides have attracted attention. InGaN and InGaNAs called the III-V nitride system are not present in semiconductor crystals other than the III-V nitride system such as InGaP and GaAs, and have a band gap of 0.8 to 1.0 eV. Therefore, highly efficient light emission and light reception are possible. In addition, a technique for changing the band gap according to the composition of the nitride to be doped has been reported, and a high-quality nitride-based semiconductor crystal is expected to be applied. In particular, in recent years, expectations are increasing in the field of solar cells that are highly desired to be highly efficient.

In the production of these semiconductor crystals, an organometallic gas such as trimethylgallium (TMG) or trimethylaluminum (TMA) and a hydrogen compound gas such as ammonia (NH ₃ ), phosphine (PH ₃ ), or arsine (AsH ₃ ) are used. A MOCVD (Metal Organic Chemical Vapor Deposition) method in which a compound semiconductor crystal is grown by introducing it into a growth chamber as a source gas contributing to film formation is widely known.

  The MOCVD method is a method in which a compound semiconductor crystal is grown on a substrate by introducing the raw material gas together with an inert gas into a growth chamber and heating it to cause a gas phase reaction on a predetermined substrate. 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.

  In other words, it is desirable that the film formation efficiency indicating how many crystals can be formed from the source gas is high. Moreover, in order to utilize as a favorable device, it is desired that the film thickness and the composition ratio are uniform.

  FIG. 16 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 103 for introducing a reaction gas and an inert gas from a gas supply source 102 to a growth chamber 111 inside the reaction furnace 101 is connected to the growth chamber 111 inside the reaction furnace 101. A shower plate 110 having a plurality of gas discharge holes for introducing a reaction gas and an inert gas into the growth chamber 111 is installed as a gas introduction part.

  In addition, a rotating shaft 112 that can be rotated by an actuator (not shown) is installed in the center of the lower portion of the growth chamber 111 of the reaction furnace 101, and a susceptor 108 is attached to the tip of the rotating shaft 112 so as to face the shower plate 110. ing. A heater 109 for heating the susceptor 108 is attached to the lower part of the susceptor 108.

  Further, a gas exhaust unit 104 for exhausting the gas in the growth chamber 111 inside the reaction furnace 101 to the outside is installed at the lower part of the reaction furnace 101. This gas exhaust unit 104 is connected via a purge line 105 to an exhaust gas treatment device 106 for rendering the exhausted gas harmless.

  When a compound semiconductor crystal is grown in the vertical showerhead type MOCVD apparatus having the above configuration, the substrate 107 is placed on the susceptor 108, and then the susceptor 108 is rotated by the rotation of the rotating shaft 112. Then, the substrate 107 is heated to a predetermined temperature through the susceptor 108 due to the heating of the heater 109, and the reaction gas and non-reacting gas are supplied from the plurality of gas discharge holes formed in the shower plate 110 to the growth chamber 111 inside the reaction furnace 101. An active gas is introduced.

  As a method of forming a thin film by supplying a plurality of reaction gases and reacting them on the substrate 107, conventionally, a plurality of gases are mixed in a shower head, and the substrate is discharged from a gas discharge port provided in a large number in the shower plate 110. 107 was used to blow out the reaction gas.

In recent years, a method in which a buffer area is provided for each of a plurality of supply gases and each reaction gas is supplied from the buffer area to the growth chamber in a separated state through the gas discharge holes of the shower plate 110 is generally used. . This is to avoid a gas phase reaction in the showerhead. Since the group III-based gas discharge holes and the group V-based gas discharge holes are alternately arranged close to each other, a group III-based gas buffer such as the reaction vessel 200 disclosed in Patent Document 1 shown in FIG. A laminated structure is often used in which the area 201 and the buffer area 202 for the V group-based gas are arranged in two layers above and below, and the gas flow paths are separated so that the gases do not mix outside the growth chamber 203.
JP-A-8-91989 (published on April 9, 1996) Japanese Patent Laid-Open No. 2002-151488 (released on February 24, 2002) JP 2002-8995 A (published on January 11, 2002)

  However, in the conventional vapor phase growth apparatus disclosed in Patent Document 1, a path through which a gas passes is installed in either the group III-based gas buffer area 201 or the group V-based gas buffer area 202. For this reason, the gas flows differ in the buffer areas 201 and 202 for both gases. As a result, there is a problem that the gas flow supplied from the gas discharge hole to the growth chamber 203 may be nonuniform between the two gases. For this reason, the film thickness and the composition ratio are not uniform. In addition, since the film formation conditions are not stable and film formation cannot be performed under optimum conditions, the film formation efficiency also deteriorates.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to supply gas from a gas discharge hole to a growth chamber when supplying at least two kinds of reaction gases into the growth chamber using a shower plate. Another object of the present invention is to provide a vapor phase growth apparatus and a method for manufacturing a semiconductor element that can make the gas flow uniform.

  In order to solve the above problems, the vapor phase growth apparatus of the present invention has a plurality of first source gas discharge holes and a plurality of second source gas discharge holes for independently discharging the first source gas and the second source gas, respectively. In a vapor phase growth apparatus for forming a film formation substrate by mixing in the growth chamber and supplying the film formation substrate to a growth chamber containing a film formation substrate via a shower plate provided with The second source gas intermediate chamber and the first source gas intermediate chamber, which are separated from each other and filled with the second source gas and the first source gas, are stacked in this order, and the second source gas intermediate chamber includes the above-mentioned A plurality of first source gas pipes communicating from the first source gas intermediate chamber to the plurality of first source gas discharge holes of the shower plate are provided through the plurality of first source gas intermediate chambers. The pillars are the second bases It is characterized in that provided in the same plane position as the gas discharge hole.

  According to the above invention, the second source gas intermediate chamber and the first source gas intermediate chamber which are separated from each other and are filled with the second source gas and the first source gas are stacked in this order on the shower plate. ing. The second source gas intermediate chamber is provided with a plurality of first source gas pipes penetrating from the first source gas intermediate chamber to the plurality of first source gas discharge holes of the shower plate.

  Therefore, after the first source gas is filled in the first source gas intermediate chamber, the growth chamber that accommodates the deposition target substrate from the plurality of first source gas pipes and the plurality of first source gas discharge holes of the shower plate. To be supplied. On the other hand, after the second source gas is filled in the second source gas intermediate chamber, the second source gas is supplied from the plurality of second source gas discharge holes of the shower plate into the growth chamber that accommodates the deposition target substrate.

  As a result, the second source gas in the second source gas intermediate chamber passes between the plurality of first source gas pipes erected in the second source gas intermediate chamber, and the plurality of second source gas discharge holes of the shower plate. It is discharged from.

  On the other hand, the first source gas in the first source gas intermediate chamber is formed in the shower plate through the plurality of first source gas pipes from the first source gas intermediate chamber, which is a large space, when there are no plurality of columns. It discharges from the some 1st source gas discharge hole.

  Therefore, due to the structural difference in the space between the first source gas intermediate chamber and the second source gas intermediate chamber, each gas flow discharged from the first source gas discharge hole and the second source gas discharge hole is between the two gases. There is a risk of non-uniformity.

  Therefore, in the present invention, the first source gas intermediate chamber is provided with a plurality of columns at the same plane position as the plurality of second source gas discharge holes. Here, since the plurality of first source gas discharge holes and the plurality of second source gas discharge holes are arranged in the shower plate, the same arrangement structure as the first source gas pipes erected in the second source gas intermediate chamber Thus, a plurality of pillars are erected in the first source gas intermediate chamber.

  As a result, the space structure of the first source gas intermediate chamber and the space structure of the second source gas intermediate chamber are the same, so the gas flow in the first source gas intermediate chamber and the gas flow in the first source gas intermediate chamber are the same. Thus, the gas flow discharged from the first source gas discharge hole through the first source gas intermediate chamber is the same as the gas flow discharged from the second source gas discharge hole through the second source gas intermediate chamber. Become.

  Therefore, when supplying at least two types of reaction gases into the growth chamber using the shower plate, the gas flow supplied from the gas discharge holes to the growth chamber can be made uniform. Thereby, the uniformity of the film thickness and composition ratio of the film formation substrate is improved, and high-quality crystal growth is possible. In addition, since the film formation conditions are stable, film formation under optimum conditions is possible, so that the film formation efficiency can be improved.

  In the vapor phase growth apparatus of the present invention, it is preferable that a column heating means for heating a plurality of columns in the first source gas intermediate chamber is provided.

  Thus, the column heating means heats the plurality of columns dispersed and arranged in the first source gas intermediate chamber, so that the first source gas in the first source gas intermediate chamber is heated uniformly. As a result, the first source gas is activated by heating, and the dope during film formation can be promoted.

  As a result, the film formation efficiency is improved as compared with the film formation using the first raw material gas that is not activated. Furthermore, it is possible to obtain a desired film thickness and composition ratio. In addition, since the uniformly activated first source gas is supplied, the uniformity of film thickness and composition ratio is improved, and high-quality crystal growth is possible.

  In the vapor phase growth apparatus of the present invention, it is preferable that the first source gas intermediate chamber in which the plurality of pillars are heated is provided in a layer farthest from the shower plate.

  That is, when a layer to be heated is disposed between the source gas layer that does not require heating and the shower plate, both measures for preventing direct heat conduction from the column heating means to the adjacent layer that does not require heating are provided. Necessary for adjacent layers.

  However, in the present invention, the first source gas intermediate chamber in which the plurality of pillars are heated is provided in a layer farthest from the shower plate, so that the heat conduction prevention measure is sufficient in one adjacent layer.

  In the vapor phase growth apparatus according to the present invention, it is preferable that the plurality of columns in the first source gas intermediate chamber are made of a heat conductive material.

  As a result, the plurality of pillars in the first source gas intermediate chamber are heated in a short time, so that the first source gas in the first source gas intermediate chamber can be heated with high efficiency.

  In the vapor phase growth apparatus of the present invention, the plurality of columns in the first source gas intermediate chamber are made of a material having good thermal conductivity on the opposite side to the second source gas intermediate chamber, and the second The source gas intermediate chamber side is preferably made of a material having a lower thermal conductivity than the side opposite to the second source gas intermediate chamber.

  As a result, the thermal conductivity of the first source gas intermediate chamber to the boundary plate with the second source gas intermediate chamber is deteriorated, so that the first source gas intermediate chamber is transferred to the boundary plate with the second source gas intermediate chamber. The influence of local heating on the second source gas filled in the second source gas intermediate chamber due to heat can be prevented. Moreover, since it can reduce that a heat | fever escapes from several pillars to the boundary board with the 2nd source gas intermediate chamber in the 1st source gas intermediate chamber, activation of the 1st source gas with which the 1st source gas intermediate chamber is filled up Can be carried out efficiently and energy saving.

  In the vapor phase growth apparatus of the present invention, it is preferable that the plurality of columns in the first source gas intermediate chamber are provided with a gap between the boundary plate and the second source gas intermediate chamber. .

  Accordingly, the plurality of columns do not contact the boundary plate with the second source gas intermediate chamber in the first source gas intermediate chamber while ensuring the rectifying function, so the second source material in the first source gas intermediate chamber from the plurality of columns. The thermal conductivity to the boundary plate with the gas intermediate chamber is deteriorated. As a result, the influence of local heating on the second source gas filled in the second source gas intermediate chamber due to heat transfer to the boundary plate with the second source gas intermediate chamber in the first source gas intermediate chamber is prevented. be able to. Moreover, since it can reduce that a heat | fever escapes from several pillars to the boundary board with the 2nd source gas intermediate chamber in the 1st source gas intermediate chamber, activation of the 1st source gas with which the 1st source gas intermediate chamber is filled up Can be carried out efficiently and energy saving.

  In the vapor phase growth apparatus of the present invention, it is preferable that the plurality of columns in the first source gas intermediate chamber are tapered on the side of the boundary plate with the second source gas intermediate chamber.

  Accordingly, the contact area of the first source gas intermediate chamber with the boundary plate with the second source gas intermediate chamber is reduced while ensuring the rectifying function, and the second source material in the first source gas intermediate chamber is reduced from the plurality of columns. The thermal conductivity to the boundary plate with the gas intermediate chamber is deteriorated. As a result, the influence of local heating on the second source gas filled in the second source gas intermediate chamber due to heat transfer to the boundary plate with the second source gas intermediate chamber in the first source gas intermediate chamber is prevented. be able to. Moreover, since it can reduce that a heat | fever escapes from several pillars to the boundary board with the 2nd source gas intermediate chamber in the 1st source gas intermediate chamber, activation of the 1st source gas with which the 1st source gas intermediate chamber is filled up Can be carried out efficiently and energy saving.

  Further, in the vapor phase growth apparatus of the present invention, the plurality of columns in the first source gas intermediate chamber are arranged at the same plane position as the plurality of first source gas discharge holes, and the boundary plate with the second source gas intermediate chamber Between the second source gas intermediate chamber and the shower plate in the second source gas intermediate chamber at the same plane position as the plurality of second source gas discharge holes. It is preferable that a plurality of pillars are provided with a gap between them or a boundary plate on the shower plate side.

  Thereby, since the number of columns in the first source gas intermediate chamber is increased, the first source gas in the first source gas intermediate chamber is heated in a shorter time. Therefore, the heating of the first source gas in the first source gas intermediate chamber can be performed with higher efficiency.

  In this case, each gas flow of the first source gas and the second source gas is changed by increasing the number of columns in the first source gas intermediate chamber. In this regard, in the present invention, the second source gas intermediate chamber has a plurality of columns with a gap between the second source gas intermediate chamber and the floor surface in the same plane position as the plurality of second source gas discharge holes. Is provided.

  Therefore, since the structural identity of the spaces of the first source gas intermediate chamber and the second source gas intermediate chamber is ensured, the gas flows of the first source gas and the second source gas change. Absent.

  In the vapor phase growth apparatus of the present invention, it is preferable that the plurality of columns in the first source gas intermediate chamber have a polygonal cross-sectional shape perpendicular to the standing direction.

  Thereby, since the surface area of a pillar increases compared with a circle, heating of the 1st source gas in the 1st source gas intermediate room can be performed more efficiently.

  In the vapor phase growth apparatus of the present invention, it is preferable that the plurality of columns in the first source gas intermediate chamber have fins.

  Thereby, since the surface area of the column increases, the heating of the first source gas in the first source gas intermediate chamber can be performed with higher efficiency.

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

  As a result, the space structure of the group V gas that is the first source gas intermediate chamber is the same as the space structure of the group III gas that is the second source gas intermediate chamber, so that the gas flow in the first source gas intermediate chamber is the same. And the first raw material gas intermediate chamber have the same gas flow, whereby the gas flow of the group V gas discharged from the first raw material gas discharge hole through the first raw material gas intermediate chamber and the second raw material gas intermediate chamber After that, the gas flow of the group III-based gas discharged from the second source gas discharge hole is the same.

  Therefore, when supplying at least two types of reaction gases of group III gas and group V gas into the growth chamber using the shower plate, the gas flow supplied from the gas discharge hole to the growth chamber is made uniform. Can do. Thereby, the uniformity of the film thickness and composition ratio of the film formation substrate is improved, and high-quality crystal growth is possible. In addition, since the film formation conditions are stable, film formation under optimum conditions is possible, so that the film formation efficiency can be improved.

  In the vapor phase growth apparatus of the present invention, the group V gas is preferably a gas containing ammonia.

  This makes it possible to make the film thickness and composition ratio uniform and improve the film formation efficiency in the group III-V crystal growth, for example, nitride. That is, for example, in the case of crystal growth of a group III-V nitride such as InGaN or InGaNAs, reaction other than the deposition target substrate, thermal decomposition, generation of holes in the growth film, and the like occur. Low temperature growth at 600 ° C. or lower is performed. In this case, at a low temperature of 600 ° C. or lower, the ammonia molecules are not activated and it is difficult for the growth film to be doped with N atoms.

  However, according to the present invention, only the group V gas containing ammonia can be heated to 800 ° C. and the activated gas can be supplied to the growth chamber. As a result, the film formation efficiency is remarkably improved as compared with the case of film formation using a group V gas that is not activated. Furthermore, it is possible to obtain a desired film thickness and composition ratio. Further, since the uniformly activated group III-based gas and group V-based gas are supplied, the uniformity of the film thickness and composition ratio is improved, and high-quality crystal growth is possible.

  In the vapor phase growth apparatus of the present invention, it is preferable that the plurality of first source gas discharge holes and the plurality of second source gas discharge holes have smaller hole diameters in the peripheral part of the shower plate than in the central part.

  As a result, a large amount of the first source gas and the second source gas are discharged to the periphery of the shower plate, thereby preventing a reaction other than the deposition target substrate, thermal decomposition, generation of holes in the growth film, and the like. can do.

  In the vapor phase growth apparatus of the present invention, the shower plate is preferably provided with an inert gas discharge hole between the first source gas discharge hole and the second source gas discharge hole.

  Thereby, the clogging of the first source gas discharge hole and the second source gas discharge hole in the shower plate can be prevented.

  The semiconductor element manufacturing method of the present invention is characterized in that a semiconductor element is manufactured using the vapor phase growth apparatus described above in order to solve the above-mentioned problems.

  According to the above invention, when supplying at least two kinds of reaction gases into the growth chamber using the shower plate, the semiconductor using the vapor phase growth apparatus that can make the gas concentration distribution on the deposition target substrate uniform. An element manufacturing method can be provided.

  As described above, the vapor phase growth apparatus according to the present invention includes the second source gas intermediate chamber and the first source gas which are isolated from each other and fill the shower plate with the second source gas and the first source gas, respectively. Intermediate chambers are stacked in this order, and the second source gas intermediate chamber has a plurality of first source gas pipes communicating from the first source gas intermediate chamber to the plurality of first source gas discharge holes of the shower plate. The first source gas intermediate chamber is provided with a plurality of columns at the same plane position as the plurality of second source gas discharge holes.

  Moreover, the manufacturing method of the semiconductor element of this invention is a method of manufacturing a semiconductor element using the above-mentioned vapor phase growth apparatus as mentioned above.

  Therefore, when supplying at least two types of reaction gases into the growth chamber using a shower plate, a vapor phase growth apparatus and a semiconductor element capable of uniformizing the gas flow supplied from the gas discharge holes to the growth chamber There is an effect of providing a manufacturing method.

An embodiment of the present invention will be described with reference to FIGS. 1 to 15 as follows. In the drawings of the present embodiment, the same reference numerals denote the same or corresponding parts.
(Basic configuration of the device)
FIG. 2 shows an example of a schematic configuration of a vertical showerhead type MOCVD apparatus 10 which is an example of a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus as a vapor phase growth apparatus of the present invention. .

  As shown in FIG. 2, the MOCVD apparatus 10 of the present embodiment has a reaction furnace 2 having a growth chamber 1 that is a hollow portion, a susceptor 4 on which a deposition target substrate 3 is placed, and the susceptor 4. And a shower head 20 having a shower plate 21 on the bottom surface.

  A heater 5 and a support base 6 for heating the deposition substrate 3 are provided below the susceptor 4, and a rotating shaft 7 attached to the support base 6 is rotated by an actuator or the like (not shown). 4 and the heater 5 are configured to rotate while maintaining a state in which the upper surface of the susceptor 4 (the surface on the shower plate 21 side) is parallel to the facing shower plate 21. A cover plate 8 serving as a heater cover is provided around the susceptor 4, the heater 5, the support base 6 and the rotary shaft 7 so as to surround the susceptor 4, the heater 5, the support base 6 and the rotary shaft 7. .

  The MOCVD apparatus 10 includes a gas discharge unit 11 for discharging the gas inside the growth chamber 1 to the outside, a purge line 12 connected to the gas discharge unit 11, and an exhaust gas connected to the purge line 12. And a processing device 13. Thereby, the gas introduced into the inside of the growth chamber 1 is discharged to the outside of the growth chamber 1 through the gas discharge unit 11, and the discharged gas is introduced into the exhaust gas treatment device 13 through the purge line 12. 13 is detoxified.

  Furthermore, the MOCVD apparatus 10 includes a group III gas supply source 31 serving as a source of a group III gas as a second source gas containing a group III element, and a group III supplied from the group III gas supply source 31. Group III gas supply amount adjustment capable of adjusting the supply amount of the group III gas supplied from the group III gas pipe 32 and the group III gas supply source 31 for supplying the system gas to the shower head 20 And a mass flow controller 33 as a unit. The group III gas supply source 31 is connected to a group III gas supply unit 23 of the shower head 20 via a mass flow controller 33 by a group III gas pipe 32.

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

  In addition, the MOCVD apparatus 10 includes a group V gas supply source 34 serving as a source of a group V gas as a first source gas containing a group V element, and a group V supplied from the group V gas supply source 34. V group gas supply amount adjustment that can adjust the supply amount of the V group gas supplied from the V group gas pipe 35 and the V group gas supply source 34 for supplying the system gas to the shower head 20 And a mass flow controller 36 as a unit. The group V gas supply source 34 is connected to the group V gas supply unit 24 of the shower head 20 through a mass flow controller 36 by a group V gas pipe 35.

In this embodiment, examples of the group V element include N (nitrogen), P (phosphorus), and As (arsenic), and examples of the group V gas including the group V element include ammonia ( One or more of hydrogen compound gases such as NH ₃ ), phosphine (PH ₃ ), or arsine (AsH ₃ ) can be used.

  The mass flow controllers 33 and 36 are controlled by a control unit (not shown).

The cold water supply unit 22 is supplied with cold water from a water cooling device 38 through a cold water system pipe 37. In the present embodiment, the cold water supply unit 22 supplies the cooling water, but is not necessarily limited to water, and other liquid and gas refrigerants can be used.
(Configuration of shower head)
<Description of basic configuration>
The configuration of the shower head 20 will be described with reference to FIG.

  As shown in FIG. 1, the shower head 20 includes, in order from the bottom, a shower plate 21, a cold water supply unit 22, a group III gas supply unit 23, a group V gas supply unit 24, and temperature adjustment as a column heating unit. The mechanism 25 is laminated.

  Since the shower plate 21, the cold water supply unit 22, the group III-based gas supply unit 23, and the group V-based gas supply unit 24 are stacked, in the present embodiment, the first raw material in the group V-based gas supply unit 24 is used. The group V gas in the group V gas buffer area 24b as the gas intermediate chamber is a group V gas as a first source gas pipe provided through the group III gas buffer area 23b and the cold water buffer area 22b. The gas is discharged into the growth chamber 1 from the group V gas discharge hole H5 as the first source gas discharge hole of the shower plate 21 through the supply pipe 24c.

  The group III gas in the group III gas buffer area 23b as the second source gas intermediate chamber in the group III gas supply unit 23 is a group III gas supply pipe provided through the cold water buffer area 22b. It is discharged into the growth chamber 1 through a group III gas discharge hole H3 as a second source gas discharge hole of the shower plate 21 through 23c.

Each will be described below.
<Description of shower plate>
FIG. 3A shows a schematic plan view of an example of the shower plate 21 used in the MOCVD apparatus 10 shown in FIG.

  The shower plate 21 has a plurality of group III gas discharge holes H3 for supplying a group III gas to the growth chamber 1 and a plurality of group V gas discharge holes H5 for supplying a group V gas. Yes. In the plane of the shower plate 21 (in the surface facing the susceptor 4), the group III-based gas discharge holes H3 and the group V-based gas discharge holes H5 are alternately arranged. In the example shown in FIG. 3A, the arrangement direction of the group III gas discharge holes H3 and the group V gas discharge holes H5 is a horizontal direction and a vertical direction. That is, it has a lattice shape. However, this lattice is not limited to a square lattice, and may be a diamond lattice. In the shower plate 21, the area of the opening of the group III gas discharge hole H3 and the area of the opening of the group V gas discharge hole H5 are the same.

  In addition, as shown in FIG.3 (b), the III group gas discharge hole H3 and the V group gas discharge hole H5 may each be provided radially, and they may be arranged by turns in the rotation direction. Further, as shown in FIG. 4, the group III-based gas discharge holes H3 and the group V-based gas discharge holes H5 may be alternately arranged in a plurality of units (in FIG. 4, every three pieces are alternately arranged). Arranged). Further, as shown in FIG. 5 (a), in the lattice arrangement shown in FIG. 3 (a), another source gas other than the group III-based gas and the group V-based gas or an inert gas is used. A discharge hole or an inert gas discharge hole may be added. When other source gas discharge holes are present, the rectifying action and the thermal decomposition action can be promoted. Further, when the inert gas discharge hole exists, there is an effect of preventing clogging of the group III gas discharge hole H3 and the group V gas discharge hole H5. From the viewpoint of preventing clogging of the group III gas discharge hole H3 and the group V gas discharge hole H5, the arrangement shown in FIGS. 5B and 5C is more effective.

  That is, as can be seen from these relationships, in the shower plate 21, the group III gas discharge hole H3 and the group V gas discharge hole H5 are other source gas discharge holes or inert gas inert gas. It can be seen that, regardless of the presence of the discharge holes, they are alternately distributed one by one or alternately every plurality.

  Next, the arrangement on the shower plate 21 of the group III-based gas discharge holes H3 and the group V-based gas discharge holes H5 in FIGS. 3 (a), 3 (b), 4 and 5 (a), 5 (b), and 5 (c). In this case, it is preferable to change the hole diameter of the group III gas discharge hole H3 and the hole diameter of the group V gas discharge hole H5 depending on the difference between the central part and the peripheral part of the shower plate 21.

  For example, in FIG. 6, the center portion 21 a and the peripheral portion 21 b of the shower plate 21 in the lattice-like arrangement in the shower plate 21 of the group III gas discharge holes H3 and the group V gas discharge holes H5 shown in FIG. The shower plate 21 when the hole diameter of the group III gas discharge hole H3 and the hole diameter of the group V gas discharge hole H5 are changed is shown. Specifically, the hole diameter is increased at the central portion 21a and the hole diameter is decreased at the peripheral portion 21b. Thereby, the flow volume of the gas in the peripheral part 21b can be suppressed.

As shown in FIG. 6, even when the hole diameters of the group III gas discharge hole H3 and the group V gas discharge hole H5 are reduced in the peripheral portion 21b, the area of the opening of the group III gas discharge hole H3 The area of the opening of the V group gas discharge hole H5 is the same. Of course, also in the central portion 21a, the area of the opening of the group III gas discharge hole H3 and the area of the opening of the group V gas discharge hole H5 are the same.
<Description of cold water supply unit>
The cold water supply unit 22 suppresses the adhesion of the reaction product to the shower plate 21 by cooling the shower plate 21 shown in FIG. 1 to a certain temperature or lower, and the group III gas discharge hole H3 and the group V gas The clogging of the discharge hole H5 is prevented. The cold water supply unit 22 has a cold water buffer area 22b provided on the shower plate 21, and cooling water flows into the cold water buffer area 22b from the side of the shower head 20, for example. It flows out from the side opposite to the head 20.
<Description of gas supply unit>
As shown in FIG. 1, the group III-based gas supply unit 23 uniformly introduces the group III-based gas supplied from, for example, the peripheral portion of the shower head 20 to the group III-based gas discharge hole H3. The annular flow path 23a, a group III gas buffer area 23b as a second source gas intermediate chamber, and a group III gas supply pipe 23c communicating with the growth chamber 1 from the group III gas buffer area 23b. . The cross section of the group III-based gas supply pipe 23c is not necessarily limited to a circle, and may be a square pipe, an elliptic pipe, or other cross sections. In the present invention, when the cold water supply unit 22 is not provided, the group III gas supply pipe 23c may not be provided. In this case, the group III gas in the group III gas buffer area 23b is discharged from the group III gas discharge hole H3.

  On the other hand, similarly, the group V gas supply unit 24 uniformly guides the reaction gas supplied from the peripheral portion of the shower head 20 to the group V gas discharge hole H5. The group V gas buffer area 24b and the group V gas supply pipe 24c are configured. Note that the cross section of the group V gas supply pipe 24c is not necessarily limited to a circular shape, and may be a square tube, an elliptic tube, or other cross sections.

  Here, FIG. 7 is a perspective view of the group V gas outer ring passage 24a (the structure of the group III gas outer ring passage 23a is the same, and the description thereof is omitted).

  For example, the V group gas supplied from the lateral direction of the V group gas outer ring passage 24a is a partition 24d with an opening having a plurality of openings H that are evenly arranged on the inner peripheral side of the V group gas outer ring passage 24a. Then, the gas is supplied uniformly to the group V gas buffer area 24b in the circumferential direction. The V group gas in the V group gas buffer area 24b is supplied to the growth chamber 1 from the V group gas discharge hole H5 through the plurality of V group gas supply pipes 24c.

  That is, as shown in FIG. 1, a group V gas supply pipe 24 c is arranged in the group III gas buffer area 23 b so as not to mix the respective gases. That is, in the plane of the group III gas buffer area 23b, the group III gas supply gas communicated from the group III gas buffer area 23b to the group III gas discharge hole H3 is provided at the position of the group III gas discharge hole H3. A pipe 23c is disposed, and a group V gas supply pipe 24c communicating from the group V gas buffer area 24b to the group V gas discharge hole H5 is provided at the position of the group V gas discharge hole H5. It will be so forested.

  Further, in the present embodiment, as shown in FIG. 1, a dummy column 25c as a column is arranged in the group V gas buffer area 24b at the same plane position as the group III gas discharge hole H3. That is, the dummy column 25c is provided at the same position on the same plane as the group III-based gas supply pipe 23c, and the planar shape thereof has the same planar shape as that of the group III-based gas supply pipe 23c.

  Thereby, the gas flows in the group III gas buffer area 23b and the group V gas buffer area 24b can be made the same, and the gas supplied to the growth chamber 1 in the group III gas and the group V gas. It is supposed to have a rectifying function that can be made equal in distribution.

  By the way, in the crystal growth, it is necessary to consider the temperature at which the gas phase reaction is performed.

  That is, in the growth of a III-V group semiconductor crystal, a metal gas is generally used as the group III gas, and an organic gas is often used as the group V gas.

  Here, when the temperature in the gas phase reaction is too high, the metal gas reacts on a substrate other than the growth substrate such as the wall surface of the processing chamber, leading to a decrease in film formation efficiency. In addition, if a reaction occurs in the gas discharge hole, which is a communication portion from the buffer area to the processing chamber, the gas discharge hole may be clogged. When the gas discharge hole is clogged, the diameter of the gas discharge hole is changed and the gas flow conditions are changed, so that it is impossible to obtain a desired film quality and growth rate. In addition, the film quality and the growth rate may be deteriorated due to re-evaporation of the growth film or generation of holes in the growth film.

  On the other hand, if the temperature in the gas phase reaction is too low, the reaction hardly proceeds and the growth rate may be deteriorated. In addition, the film quality and growth rate may be deteriorated, for example, molecules are decomposed and are not doped into the growth film, or molecules are doped as they are to form holes.

  In either case, inconvenience arises for use in the device. For this reason, it is desirable that the gas phase reaction be performed at an optimum temperature.

  For example, when crystal growth of InGaN, InGaNAs or the like is performed, if the temperature is raised to 600 ° C. or higher, the grown crystal is thermally decomposed and holes are generated in the growth film. For this reason, electrical conductivity deteriorates remarkably and cannot be used as a device. Moreover, at 500-600 degreeC, the ammonia molecule | numerator often used as a nitride-type material gas is not decomposed | disassembled, N atom is hard to dope to a growth film | membrane, and it does not use as a device.

  Therefore, by heating the group V gas outside the film formation zone in advance and supplying the activated gas to the film formation zone, the substrate temperature is maintained at a temperature at which the group III gas is not thermally decomposed. Techniques for advancing gas phase reactions are known.

  For example, in Patent Document 2, as shown in FIG. 18, a method of preheating gas with a preheater 302 in a gas pipe channel 301 upstream of a film formation region is proposed.

  In Patent Document 3, as shown in FIG. 19, there is a method of supplying activated gas to a film formation region by heating the vicinity of a gas discharge port for supplying gas to the film formation region with a heater 401. Proposed.

  However, in Patent Document 2 and Patent Document 3, since the heat distribution is not uniform, the uniformly activated gas is not necessarily supplied to the growth chamber from the V group gas discharge hole.

  For example, in Patent Document 2, the gas in the gas pipe channel 301 that has been preheated and the gas in the gas pipe channel 303 that has not been heated are mixed on the upstream side of the shower head 304, Since the reaction takes place before it reaches, the film formation efficiency is expected to decrease.

  Further, the heated gas in the gas pipe flow path 301 is cooled while passing through the pipe in the gas pipe flow path 303 and the shower head 304, and there is a possibility that the fully activated gas is not supplied to the growth chamber 305. . Furthermore, since it is affected by the passage distance and route, the distribution of the activated gas tends to be non-uniform.

  For example, in patent document 3, the periphery of the shower plate 402 or the gas discharge holes 403 and 404 is heated. When the entire shower plate 402 is heated, a growth film is formed on the gas exposed surface, which may reduce the growth rate. Furthermore, if a growth film is formed in the vicinity of the gas discharge holes 403 and 404, the gas discharge holes 403 and 404 may be clogged. By clogging, the diameters of the gas discharge holes 403 and 404 are changed, and the gas flow conditions are changed. Therefore, desired film quality and growth rate cannot be obtained.

  Furthermore, it is necessary to set the heating temperature to a temperature at which one gas does not react and the other gas decomposes. However, as described above, when ammonia is used as the group V gas, the material is limited because it is necessary to use a group III gas that does not react at the temperature at which ammonia is activated. At least, since the InN-based crystal is decomposed again, film formation by the method of Patent Document 3 is difficult.

  Therefore, in the present embodiment, by providing the temperature adjusting mechanism 25 incorporating a heater (not shown), it is possible to heat the V group gas in the V group gas buffer area 24b and to adjust the heating temperature. It has become.

  The dummy column 25c is provided so as to hang down from the temperature adjustment mechanism 25. When the temperature adjustment mechanism 25 is heated, the dummy column 25c is thermally conducted to the dummy column 25c made of a material having good thermal conductivity. ing. As a result, the V group gas in the V group gas buffer area 24b comes into contact with the bottom surface of the temperature adjusting mechanism 25 and the surface of the dummy column 25c to be heated.

  As a result, the V group gas in the V group gas buffer area 24b can be efficiently heated.

  Here, in the present embodiment, the dummy column 25c is provided in contact with the floor surface of the group V gas buffer area 24b as shown in FIG. However, the present invention is not necessarily limited thereto. For example, as shown in FIG. 8, the dummy pillar 25c may be slightly separated from the boundary plate 41 that is the floor surface of the group V gas buffer area 24b. .

  This is because the dummy column 25c is not in contact with the boundary plate 41 between the group V gas buffer area 24b and the group III gas buffer area 23b while ensuring a rectifying function. This is to prevent the influence of local heating on the group III gas filled in the group gas buffer area 23b. In addition, since the heat escape from the dummy pillar 25c to the boundary plate 41 can be reduced, the group V gas filled in the group V gas buffer area 24b can be activated efficiently and energy saving can be achieved.

  Further, as shown in FIG. 9, the dummy pillar 25c can be formed so as to taper downward, and for example, a member 42 having poor heat conduction can be provided at the tip thereof. It is.

  As a result, the area of contact with the boundary plate 41 is reduced while ensuring the rectifying function, and the thermal conductivity to the boundary plate 41 is deteriorated. Therefore, in the group III gas buffer area 23b due to heat transfer of the boundary plate 41, The influence of local heating on the group III gas to be filled can be prevented. In addition, since the heat escape from the dummy pillar 25c to the boundary plate 41 can be reduced, the group V gas filled in the group V gas buffer area 24b can be activated efficiently and energy saving can be achieved.

  Further, in addition to the configuration of FIG. 8, the dummy column 25c is further provided with a dummy column 43 concentrically and slightly separated from the group V gas supply pipe 24c as shown in FIG. It can be provided concentrically and slightly apart from the group III gas supply pipe 23c.

  As a result, the dummy column 25c is not in contact with the boundary plate 41 while ensuring a rectifying function, so that local heating of the group III gas filled in the group III gas buffer area 23b by heat transfer of the boundary plate 41 is performed. Can be prevented. In addition, since the heat escape from the dummy pillar 25c to the boundary plate 41 can be reduced, the group V gas filled in the group V gas buffer area 24b can be activated efficiently and energy saving can be achieved.

  Further, since the dummy column 25c is arranged in the same plane as the group V gas supply pipe 24c, the gas flow of the group V gas in the group V gas buffer area 24b and the group III system in the group III gas buffer area 23b. The gas flow of gas can be made the same.

  Further, since the dummy column 25c is located immediately above the opening that flows from the V group gas buffer area 24b to the V group gas supply pipe 24c, the dummy column 25c passes through the vicinity of the dummy column 25c where the V group gas is heated. It flows into the group-based gas supply pipe 24c. Therefore, since the group V gas is reliably heated, the group V gas can be reliably activated.

  In addition, when using not only III group gas and V group gas but other source gas or inert gas as source gas, the shower head 20 also becomes multistage. In this case, the dummy column 25c and the like can be arranged as follows.

  For example, in the method of disposing the group III gas discharge hole H3 and the group V gas discharge hole H5 shown in FIG. 5A, as shown in FIG. Other than the gas or the inert gas, the gas buffer area 26b can be used. In this case, in addition to the configuration shown in FIG. 10, the other gas buffer area 26b is provided with a dummy column 45 concentrically and slightly separated from the other gas supply pipe 26c, and the first group V-group gas. Also in the buffer area 24b, a dummy column 46 is provided concentrically with the dummy column 45 and slightly separated from the boundary plate 41. Further, in the other gas buffer area 26b, a dummy column 47 is further provided concentrically with the group III-based gas supply pipe 23c and slightly separated from the boundary plate 41a.

  On the other hand, for example, in the arrangement method of the group III gas discharge hole H3 and the group V gas discharge hole H5 shown in FIG. 5B, as shown in FIG. In addition to the source gas or the inert gas, the gas buffer area 26b can be used. In this case, in addition to the configuration shown in FIG. 10, the other gas buffer area 26b is provided with a dummy column 45 concentrically and slightly separated from the other gas supply pipe 26c, and the first group V-group gas. Also in the buffer area 24b, a dummy column 46 is provided concentrically with the dummy column 45 and slightly separated from the boundary plate 41. In the other gas buffer area 26b, a dummy column 48 is further provided concentrically with the group III-based gas supply pipe 23c and slightly separated from the boundary plate 41a.

  In the example shown in FIGS. 11 (a) and 11 (b), the second layer is the other gas buffer area 26b other than the source gas or the inert gas. In addition to the source gas or the inert gas, the gas buffer area can be used. In this case, for example, in the example corresponding to FIG. 11 (a), as shown in FIG. 12, the group III gas buffer area 23b of the second layer is concentrically and slightly separated from the group III gas supply pipe 23c. The dummy pillars 44 are provided. In the V-group gas buffer area 24b as the first layer, a dummy column 46 is provided concentrically with the dummy column 44 and slightly separated from the boundary plate 41, and concentrically and slightly with the group V gas supply pipe 24c. It is possible to provide the dummy pillars 43 at a distance. If the third layer is an inert gas, the other gas buffer area 27b may not have a dummy column.

  The dummy pillar 25c may be solid or hollow. In the case of being hollow, for example, the heating fluid can be refluxed as the temperature adjustment mechanism 25.

  Further, the planar shape of the dummy pillar 25c is not limited to a circle, and may be, for example, a polygonal shape shown in FIGS. 13A to 13C, as shown in FIG. 13D. It is possible to configure a plurality of pieces. By adopting these shapes, the surface area of the dummy column 25c is increased while ensuring the same rectifying function as the group III gas supply pipe 23c, so that the heat transfer to the group V gas is improved, and the group V system is improved. Gas activation can be performed efficiently.

Moreover, the dummy pillar 25c can be provided with a plurality of fins 49 as shown in FIG. Also with this configuration, the surface area of the dummy column 25c is increased by the fins 49, so that the heat transfer to the V group gas is improved, and the activation of the V group gas can be performed efficiently.
(Explanation of growth method)
Next, a method of manufacturing a group III-V compound semiconductor by growing a group III-V compound semiconductor crystal by the MOCVD method using the MOCVD apparatus 10 of the present embodiment will be described with reference to FIGS. .

  When the III-V compound semiconductor crystal is grown by the MOCVD method using the MOCVD apparatus 10 of the present embodiment having the configuration shown in FIG. 2, first, the deposition target substrate 3 on the susceptor 4 is formed. Installed. Thereafter, the surface of the film formation substrate 3 installed on the upper surface of the susceptor 4 is rotated while maintaining the state parallel to the shower plate 21 by the rotation of the rotating shaft 7, and is heated via the susceptor 4 by the heating of the heater 5. The film formation substrate 3 is heated to a predetermined temperature. A group III-based gas is introduced into the growth chamber 1 from the group III-based gas discharge hole H3 formed in the shower plate 21 in a direction perpendicular to the surface of the deposition target substrate 3, and also into the shower plate 21. A V group gas is introduced into the growth chamber 1 through the formed V group gas discharge hole H5 in a direction perpendicular to the surface of the deposition target substrate 3. Thereby, a group III-V compound semiconductor crystal grows on the surface of the deposition target substrate 3. Here, the supply amount of the group III gas and the supply amount of the group V gas are controlled by the mass flow controllers 33 and 36 by a control unit (not shown), and each of the group III gas and the group V gas grows. It will be supplied to the chamber 1.

  The group III gas and the group V gas are supplied from the group III gas discharge holes H3 and the group V gas discharge holes H5 alternately arranged on the shower plate 21, respectively. The uneven distribution of the group III gas discharge holes H3 and the group V gas discharge holes H5 above the surface can be reduced.

  The group III gas and the group V gas are mixed to make the concentration distribution uniform, and coupled with the heating of the deposition substrate 3 by the heater 5, the gas phase reaction between the group III gas and the group V gas is performed. The process proceeds in the vicinity of the surface of the film formation substrate 3.

  Here, the heating by the heater 5 is set to a predetermined temperature. The reason will be described below.

  First, when the temperature in the gas phase reaction is too high, the group III-based gas reacts on a wall other than the film formation substrate 3 such as the wall surface of the growth chamber 1 and leads to a decrease in film formation efficiency. Further, the group III gas and the group V gas introduced into the growth chamber 1 from the group III gas buffer area 23b and the group V gas buffer area 24b are the group III gas discharge hole H3 and the group V gas discharge hole, respectively. If the reaction is caused by H5, the group III gas discharge hole H3 and the group V gas discharge hole H5 may be clogged. When clogged, the diameters of the group III-based gas discharge holes H3 and the group V-based gas discharge holes H5 change, and the gas flow conditions change, so that it becomes impossible to obtain a desired film quality and growth rate. In addition, the film quality and growth rate may be deteriorated due to re-evaporation of the growth film, generation of holes in the growth film, and the like.

  Next, if the temperature is too low, the reaction hardly proceeds and the growth rate may be deteriorated. In addition, the film quality and the growth rate may be deteriorated, for example, molecules are decomposed and are not doped into the growth film, or molecules are doped as they are to form holes. In either case, inconvenience arises for use in the device.

  For example, when crystal growth of InGaN, InGaNAs or the like is performed, if the temperature is raised to 600 ° C. or higher, the grown crystal is thermally decomposed and holes are generated in the growth film, so that the conductivity is significantly deteriorated and cannot be used as a device. Moreover, at 500-600 degreeC, the ammonia molecule | numerator often used as a nitride-type material gas is not decomposed | disassembled, N atom is hard to dope to a growth film | membrane, and it does not use as a device.

  Therefore, it is desirable that the gas phase reaction be performed at the optimum temperature.

  In the present embodiment, in addition to the temperature control of the heater 5, as shown in FIG. 1, the dummy column 25 c is heated by the temperature adjustment mechanism 65 provided in the top plate portion of the shower head 20, thereby The buffer area 24b is set to have a desired temperature. The temperature adjustment mechanism 25 includes a heating mechanism and a temperature control unit, and a temperature sensor for measuring the temperature in the group V gas buffer area 24b. In the present embodiment, for example, a thermocouple is attached to a wall surface and measured.

  The dummy column 25c only needs to satisfy the specifications of the apparatus in consideration of thermal conductivity, corrosion resistance, heat resistance, durability, and the like for the supplied gas. If it has a good thermal conductivity, it can be heated efficiently. In the present embodiment, for example, Mo is used from the above viewpoint. In addition, tungsten (W), gold (Au), etc. which are excellent in corrosion resistance, heat resistance, etc. may be used. What is necessary is just to select suitably according to a specification.

  Here, in the present embodiment, since only the group V gas is heated, it is not necessary to consider the reaction of the group III gas other than the deposition target substrate 3, and the temperature can be set to a desired temperature. Furthermore, the dummy pillar 25c is arranged in a forest on the entire group V gas buffer area 24b. By applying heat equally to the dummy pillars 25c, the group V gas in the group V gas buffer area 24b can be heated uniformly. In addition, the gas flow in the group III gas buffer area 23b and the group V gas buffer area 24b is uniformly heated while maintaining the same gas flow.

  In the above description, the case where a group III gas or a group V gas is introduced has been described. In the present embodiment, an inert gas or a dopant source is used together with the group III gas and the group V gas. Gas or the like may be supplied to the growth chamber 1.

  In general, the group III-based gas preferably has a relatively low temperature, and the group V-based gas preferably has a relatively high temperature. Therefore, only the group V-based gas is heated as described above. However, the present invention can be applied if the optimum temperature for crystal growth differs depending on the supply gas. That is, the dummy pillars 25c may be arranged in the gas buffer area to be set at a high temperature.

  In the above description, the case where the group III gas discharge hole H3 and the group V gas discharge hole H5 are circular has been described. In the present invention, the group III gas discharge hole H3 and the group V gas are used. The shape of the discharge hole H5 is not particularly limited, and can be, for example, a polygonal shape or an elliptical shape.

  In the above description, the case where one deposition target substrate 3 is installed has been described. However, in the present invention, not only one deposition target substrate 3 but also a plurality of deposition target substrates 3 may be installed.

  Furthermore, in the present invention, it goes without saying that the shapes of the reaction furnace 2, the shower plate 21, and other members constituting the MOCVD apparatus 10 are not limited to the shapes shown in FIG. For example, the MOCVD apparatus 10 of the present embodiment has a so-called face-up configuration in which the deposition target substrate 3 faces upward. However, the present invention is not limited to this, and the deposition target substrate 3 is not necessarily limited thereto. By supporting with a nail or the like so as not to fall, it is possible to adopt a so-called face-down configuration in which the deposition target substrate 3 faces downward.

  Finally, a specific method for manufacturing a semiconductor laser element, for example, using the above-described MOCVD apparatus 10 will be described with reference to FIG. FIG. 15 is a cross-sectional view illustrating a GaN-based semiconductor laser device 50 in a dual manner. The semiconductor element is not necessarily limited to a semiconductor laser element, and may be a semiconductor element such as an LED element.

When the semiconductor laser element 50 is manufactured, as shown in FIG. 15, first, an n-type GaN substrate 51 having a thickness of 400 μm is carried into the MOCVD apparatus 10. Next, TMG (trimethylgallium), NH ₃ , and SiH ₄ are introduced while flowing a carrier gas (H ₂ ), and Si-doped n-type GaN lower contact is applied to the n-type GaN substrate 51 at a substrate temperature of about 1125 ° C. Layer 52 is grown to a thickness of 4 μm. Subsequently, TMA (trimethylaluminum) is introduced at a predetermined flow rate, and an n-type Al _0.1 Ga _0.9 N lower cladding layer 53 having a thickness of 0.95 μm is formed under the same substrate temperature. Thereafter, the supply of TMA is stopped, and the Si-doped n-type GaN lower guide layer 54 is grown to a thickness of 0.1 μm under the same substrate temperature.

Thereafter, the supply of TMG and SiH ₄ is stopped, the carrier gas is changed from H ₂ to N ₂ , the substrate temperature is lowered to about 725 ° C., TMI (trimethylindium) and TMG are introduced, and In _V Ga _{1− A V} N (0 ≦ V ≦ 1) barrier layer is grown. Subsequently, the supply of TMI is increased to a predetermined amount, and an In _W Ga _1-W N (0 ≦ W ≦ 1) well layer is grown. The formation of an InGaN barrier layer and an InGaN well layer is repeated to form an active layer 55 including multiple quantum wells having an alternate stacked structure (barrier layer / well layer /... Well layer / barrier layer). The composition ratio and thickness between the barrier layer and the well layer made of InGaN mixed crystal are designed so that the emission wavelength is in the range of 370 to 430 nm, and the number of well layers can be, for example, three.

After the formation of the active layer 55, the supply of TMI and TMG is stopped, and the substrate temperature is increased to about 1050 ° C., which is lower than the growth temperature of the GaN-based semiconductor layers 52 to 54 below the active layer 55. Here, the carrier gas is changed from N ₂ to H ₂ , TMG, TMA, and p-type dopant biscyclopentadienylmagnesium (Cp ₂ Mg) are introduced, for example, 18 nm thick Mg-doped p-type Al _{A 0.2} Ga _0.8 N evaporation preventing layer 56 is formed.

Next, the supply of TMA is stopped, the supply amount of TMG is adjusted, and the Mg-doped p-type GaN upper guide layer 57 having a thickness of, for example, 0.1 μm is formed at the same substrate temperature. Subsequently, TMA is introduced at a predetermined flow rate to adjust the flow rate of TMG, and a p-type Al _0.1 Ga _0.9 N upper clad layer 58 having a thickness of 0.5 μm, for example, is formed at the same substrate temperature. Then, the supply of TMA is stopped, the supply amount of TMG is adjusted, and the Mg doped p-type GaN upper contact layer 59 having a thickness of, for example, 0.1 μm is formed at the same substrate temperature, thereby terminating the epitaxial crystal growth. . After the completion of crystal growth, the supply of TMG and Cp ₂ Mg is stopped to lower the substrate temperature, and the wafer is taken out from the MOCVD apparatus 10 at room temperature.

The obtained epitaxial wafer is processed into a plurality of laser element chips. First, when forming the p-type electrode portion, a striped resist having a width of 2 μm is formed on the Mg-doped p-type GaN upper contact layer 59, and the ridge stripe portion 60 is formed by reactive ion etching (RIE). Then, formed by depositing Si0 ₂ dielectric film 61 for current confinement. Next, the resist is peeled off to expose the Mg-doped p-type GaN upper contact layer 59 and deposited in the order of Pd / Mo / Au to form the p-type electrode 62.

  Thereafter, the second main surface of the n-type GaN substrate 51 is shaved by polishing or the like, so that the wafer thickness is 140 μm and the wafer is easily divided. Then, an n-type electrode 63 is formed on the second raw surface of the n-type GaN substrate 51 by vapor deposition in the order of Ti / A1. The wafer formed up to the n-type electrode is cleaved and divided into bars to form a resonator end face composed of a cleaved surface. At this time, the resonator length is set to 500 μm, for example. Thereafter, each bar is diced and divided in parallel with the ridge stripe to obtain a plurality of laser element chips.

  Through the above process, the GaN-based semiconductor laser device 50 shown in FIG. 15 is obtained.

  As described above, the MOCVD apparatus 10 according to the present embodiment includes a plurality of group V gas discharge holes for independently discharging group V gas as the first source gas and group III gas as the second source gas. It is supplied into the growth chamber 1 that accommodates the deposition target substrate 3 through the shower plate 21 provided with H5 and a plurality of group III gas discharge holes H3, and is mixed in the growth chamber 1 to be deposited. 3 is formed.

  Then, on the shower plate 21, a group III gas buffer area 23b and a group V gas buffer area 24b, which are separated from each other and are filled with a group III gas and a group V gas, are stacked in this order. In the group gas buffer area 23b, a plurality of group V gas supply pipes 24c are provided penetrating from the group V gas buffer area 24b to the group V gas discharge holes H5 of the shower plate 21.

  Accordingly, after the V group gas is filled in the V group gas buffer area 24b, the deposition target substrate is supplied from the plurality of V group gas supply pipes 24c and the plurality of V group gas discharge holes H5 of the shower plate 21. 3 is supplied into the growth chamber 1 that accommodates 3. On the other hand, the group III-based gas is supplied into the growth chamber 1 that accommodates the deposition target substrate 3 from the plurality of group-III-based gas discharge holes H3 of the shower plate 21 after the group III-based gas buffer area 23b is filled. Is done.

  As a result, the group III gas in the group III gas buffer area 23b passes through the group V gas supply pipes 24c through the group V gas supply pipes 24c established in the group III gas buffer area 23b. It is discharged from the plurality of group III gas discharge holes H3 of the shower plate 21.

  On the other hand, the V group gas in the V group gas buffer area 24b supplies a plurality of V group gases from the V group gas buffer area 24b which is a large space when the plurality of dummy pillars 25c are not present. The gas is discharged from the plurality of group V gas discharge holes H5 of the shower plate 21 through the pipe 24c.

  Therefore, due to the structural difference in space between the group V gas buffer area 24b and the group III gas buffer area 23b, each gas flow discharged from the group V gas discharge hole H5 and the group III gas discharge hole H3 is changed. There is a risk of non-uniformity between the two gases.

  Therefore, in the present embodiment, a plurality of dummy columns 25c are provided in the same plane position as the plurality of group III-based gas discharge holes H3 in the group V-based gas buffer area 24b. Here, since the plurality of group V gas discharge holes H5 and the plurality of group III gas discharge holes H3 are arranged in the shower plate 21, the group V gas supply supplied to the group III gas buffer area 23b is provided. A plurality of dummy pillars 25c are erected in the group V gas buffer area 24b with the same arrangement structure as the pipe 24c.

  As a result, the space structure of the group V gas buffer area 24b and the space structure of the group III gas buffer area 23b become the same, so that the gas flow in the group V gas buffer area 24b and the group V gas buffer area 24b As a result, the gas flow becomes the same, whereby the gas flow discharged from the group V gas discharge hole H5 through the group V gas buffer area 24b and the gas flow discharged from the group III gas discharge hole H3 through the group III gas buffer area 23b. The gas flow is the same.

  Accordingly, when supplying at least two kinds of reaction gases of group III gas and group V gas into the growth chamber 1 using the shower plate 21, the group III gas discharge holes H3 and the group V of the shower plate 21 are used. The MOCVD apparatus 10 that can make the gas flow supplied from the system gas discharge hole H5 to the growth chamber 1 uniform can be provided. This improves the uniformity of the film thickness and composition ratio of the film formation substrate 3 and enables high-quality crystal growth. In addition, since the film formation conditions are stable, film formation under optimum conditions is possible, so that the film formation efficiency can be improved.

  Further, in the MOCVD apparatus 10 of the present embodiment, a temperature adjustment mechanism 25 that heats the plurality of dummy pillars 25c in the group V gas buffer area 24b is provided.

  As a result, the temperature adjusting mechanism 25 heats the plurality of dummy pillars 25c dispersedly arranged in the group V gas buffer area 24b, so that the group V gas in the group V gas buffer area 24b is uniform. To be heated. As a result, the group V gas is activated by heating, and the dope during film formation can be promoted.

  As a result, the film formation efficiency is improved as compared with the film formation using the group V gas that is not activated. Furthermore, it is possible to obtain a desired film thickness and composition ratio. Further, since the uniformly activated group V gas is supplied, the uniformity of the film thickness and composition ratio is improved, and high-quality crystal growth is possible.

  Further, in the MOCVD apparatus 10 of the present embodiment, the V group gas buffer area 24b where the plurality of dummy pillars 25c are heated is preferably provided in a layer farthest from the shower plate 21.

  That is, when the group V gas buffer area 24b, which is a layer to be heated, is disposed between a layer of a source gas such as a group III gas that does not require heating and the shower plate 21, adjacent heating is performed. Direct heat conduction prevention measures from the column heating means to the group III gas buffer area 23b, which is an undesired layer, are required for both adjacent layers.

  However, in the present embodiment, the group V gas buffer area 24b in which the plurality of dummy pillars 25c is heated is provided in the layer farthest from the shower plate 21, so the heat conduction prevention measure is in the adjacent layer on one side. It ’s enough. For example, when the temperature adjustment mechanism 25 is provided on the side without an adjacent layer as in the present embodiment, the temperature adjustment mechanism 25 directly enters the group III-based gas buffer area 23b which is an adjacent layer where heating is not desired. No preventive measures for thermal conduction are required. In this case, if the countermeasure is insufficient, the thermal efficiency is deteriorated.

  Further, in the MOCVD apparatus 10 of the present embodiment, the plurality of dummy pillars 25c in the group V gas buffer area 24b are made of a heat conductive material. Thereby, since the plurality of dummy pillars 25c in the V group gas buffer area 24b are heated in a short time, the V group gas in the V group gas buffer area 24b can be heated with high efficiency.

  In the MOCVD apparatus 10 of the present embodiment, the plurality of dummy pillars 25c in the group V gas buffer area 24b are made of a material having good thermal conductivity on the ceiling side opposite to the group III gas buffer area 23b. In addition, the floor side, which is the group III gas buffer area 23b side, is made of a material having lower thermal conductivity than the ceiling side, which is the opposite side to the group III gas buffer area 23b. be able to.

  As a result, the thermal conductivity to the floor of the group V gas buffer area 24b is deteriorated, so that the group III gas buffer area 23b is filled by heat transfer to the floor of the group V gas buffer area 24b. The effect of local heating on the group III gas can be prevented. Moreover, since it is possible to reduce the escape of heat from the plurality of dummy pillars 25c to the floor surface of the group V gas buffer area 24b, the activation of the group V gas filled in the group V gas buffer area 24b is efficiently performed. It can be done and it saves energy.

  Further, in the MOCVD apparatus 10 of the present embodiment, the plurality of dummy pillars 25c in the group V gas buffer area 24b is the boundary plate 41 with the group III gas buffer area 23b, that is, the floor surface of the group V gas buffer area 24b. It can be assumed that it is provided with a gap therebetween.

  As a result, the plurality of dummy pillars 25c do not come into contact with the floor surface of the group V gas buffer area 24b while ensuring the rectification function, so that heat from the plurality of dummy pillars 25c to the floor surface of the group V gas buffer area 24b can be obtained. The conductivity becomes worse. As a result, the influence of local heating on the group III gas filled in the group III gas buffer area 23b due to heat transfer to the floor of the group V gas buffer area 24b can be prevented. Moreover, since it is possible to reduce the escape of heat from the plurality of dummy pillars 25c to the floor surface of the group V gas buffer area 24b, the activation of the group V gas filled in the group V gas buffer area 24b is efficiently performed. It can be done and it saves energy.

  In the MOCVD apparatus 10 of the present embodiment, the plurality of dummy pillars 25c in the group V gas buffer area 24b are tapered on the floor surface side, that is, the boundary plate 41 side with the group III gas buffer area 23b. Is preferred.

  Thereby, while ensuring the rectifying function, the contact area with the floor surface of the V group gas buffer area 24b is reduced, and the thermal conductivity from the plurality of dummy pillars 25c to the floor surface of the V group gas buffer area 24b. Becomes worse. As a result, the influence of local heating on the group III gas filled in the group III gas buffer area 23b due to heat transfer to the floor of the group V gas buffer area 24b can be prevented. Moreover, since it is possible to reduce the escape of heat from the plurality of dummy pillars 25c to the floor surface of the group V gas buffer area 24b, the activation of the group V gas filled in the group V gas buffer area 24b is efficiently performed. It can be done and it saves energy.

  Further, in the MOCVD apparatus 10 of the present embodiment, the group V gas buffer area 24b, which is the boundary plate 41 with the group III gas buffer area 23b, is also located at the same plane position as the plurality of group V gas discharge holes H5. Are provided with a plurality of dummy pillars 43 in the group V gas buffer area 24b with a gap between them and a plurality of group III gas discharge holes in the group III gas buffer area 23b. It can be assumed that a plurality of dummy pillars 44 are provided with gaps between the boundary plate on the shower plate 21 side, which is the floor surface in the group III gas buffer area 23b, at the same plane position as H3.

  As a result, the number of dummy pillars 25c and dummy pillars 44 in the group V gas buffer area 24b increases, so that the group V gas in the group V gas buffer area 24b is heated in a shorter time. Therefore, the heating of the group V gas in the group V gas buffer area 24b can be performed with higher efficiency.

  In this case, by increasing the number of dummy pillars 25c and dummy pillars 44 in the group V gas buffer area 24b, the gas flows of the group V gas and the group III gas change. In this regard, in the present embodiment, there is a gap between the group III gas buffer area 23b and the floor surface of the group III gas buffer area 23b at the same plane position as the group III gas discharge holes H3. Thus, a plurality of dummy pillars 44 are provided.

  Accordingly, the structural identity of the spaces in the group V gas buffer area 24b and the group III gas buffer area 23b is ensured, so that the gas flows of the group V gas and the group III gas change. There is nothing.

  Further, in the MOCVD apparatus 10 of the present embodiment, it is preferable that the plurality of dummy columns 25c in the group V gas buffer area 24b have a polygonal cross-sectional shape perpendicular to the standing direction.

  Thereby, since the surface area of the dummy pillar 25c increases compared with a circle, the heating of the V group gas in the V group gas buffer area 24b can be performed with higher efficiency.

  In the MOCVD apparatus 10 of the present embodiment, it is preferable that the plurality of dummy pillars 25 c in the group V gas buffer area 24 b have fins 49.

  Thereby, since the surface area of the dummy column 25c increases, the heating of the V group gas in the V group gas buffer area 24b can be performed with higher efficiency.

  Further, in the MOCVD apparatus 10 of the present embodiment, it is preferable that the first source gas is a group V gas and the second source gas is a group III gas.

  As a result, the space structure of the group V gas that is the group V gas buffer area 24b and the space structure of the group III gas that is the group III gas buffer area 23b are the same, so that the group V gas buffer area 24b And the gas flow of the group III gas buffer area 23b become the same, and thereby, the gas flow of the group V gas discharged from the group V gas discharge hole H5 through the group V gas buffer area 24b, The gas flow of the group III gas discharged from the group III gas discharge hole H3 after passing through the group III gas buffer area 23b is the same.

  Therefore, when supplying at least two types of reaction gases of group III gas and group V gas into the growth chamber 1 using the shower plate 21, the group III gas discharge holes H3 and the group V of the shower plate 21 are used. The MOCVD apparatus 10 that can make the gas flow supplied from the system gas discharge hole H5 to the growth chamber 1 uniform can be provided. This improves the uniformity of the film thickness and composition ratio of the film formation substrate 3 and enables high-quality crystal growth. In addition, since the film formation conditions are stable, film formation under optimum conditions is possible, so that the film formation efficiency can be improved.

  Further, in the MOCVD apparatus 10 of the present embodiment, the group V gas is a gas containing ammonia.

  This makes it possible to make the film thickness and composition ratio uniform and improve the film formation efficiency in the group III-V crystal growth, for example, nitride. That is, for example, when crystal growth of InGaN, InGaNAs or the like, which is a III-V group nitride system, reaction other than the deposition target substrate 3, thermal decomposition, generation of holes in the growth film, and the like occur. , Low temperature growth at 600 ° C. or lower is performed. In this case, at a low temperature of 600 ° C. or lower, the ammonia molecules are not activated and it is difficult for the growth film to be doped with N atoms.

  However, according to the present embodiment, only the group V gas containing ammonia is heated to 800 ° C., and the activated gas can be supplied to the growth chamber 1. As a result, the film formation efficiency is remarkably improved as compared with the case of film formation using a group V gas that is not activated. Furthermore, it is possible to obtain a desired film thickness and composition ratio. Further, since the uniformly activated group III-based gas and group V-based gas are supplied, the uniformity of the film thickness and composition ratio is improved, and high-quality crystal growth is possible.

  Further, in the MOCVD apparatus 10 of the present embodiment, the plurality of group V-based gas discharge holes H5 and the plurality of group III-based gas discharge holes H3 are smaller in diameter at the peripheral portion 21b of the shower plate 21 than at the central portion 21a. It is preferable.

  As a result, a large amount of group V and group III gases are discharged to the periphery of the shower plate 21, resulting in reactions other than the deposition target substrate 3, thermal decomposition, and generation of holes in the growth film. Can be prevented.

  Further, in the MOCVD apparatus 10 of the present embodiment, the shower plate 21 is preferably provided with an inert gas discharge hole between the group V gas discharge hole H5 and the group III gas discharge hole H3. .

  Thereby, clogging of the V group type gas discharge hole H5 and the III group type gas discharge hole H3 in the shower plate 21 can be prevented.

  In the manufacturing method of the semiconductor laser device 50 of the present embodiment, the semiconductor laser device 50 is manufactured using the MOCVD apparatus 10 described above.

  Therefore, when supplying at least two kinds of reaction gases into the growth chamber 1 using the shower plate 21, a semiconductor laser using the MOCVD apparatus 10 that can make the gas concentration distribution on the deposition target substrate 3 uniform. A method for manufacturing the element 50 can be provided.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention is a vapor phase growth method such as a vertical MOCVD apparatus using a shower plate that introduces a gas into the space above the shower plate from the periphery and supplies a reaction gas to the substrate surface from a plurality of gas discharge holes of the shower plate. It can utilize for the manufacturing method of an apparatus and a semiconductor element.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the vapor phase growth apparatus in this invention, and shows the structure of a shower head. It is the schematic which shows the whole structure of the said vapor phase growth apparatus. (A) is a top view which shows the structure of the shower plate in the said shower head, (b) is a top view which shows the other structure of the shower plate in the said shower head. It is a top view which shows other structure of the shower plate in the said shower head. (A)-(c) is a top view which shows the structure of the shower plate in the said shower head in the case of supplying other source gas or an inert gas in addition to a III group gas and a V group gas. . It is a top view which shows the structure of the modification of the shower plate in the shower head shown to Fig.3 (a). It is a perspective view which shows the structure of the V group type outer ring flow path of the V group type gas supply part in the said shower head. It is sectional drawing which shows the structure of the other dummy pillar of the V group type gas supply part in the said shower head. It is sectional drawing which shows the structure of the further another dummy pillar of the V group type gas supply part in the said shower head. It is sectional drawing which shows the structure of the further another dummy pillar of the V group type gas supply part in the said shower head. (A) is sectional drawing which shows the structure of the dummy pillar in the said shower head corresponding to Fig.5 (a), (b) is a cross section which shows the structure of the dummy pillar in the said showerhead corresponding to FIG.5 (b). FIG. It is sectional drawing which shows the structure of a dummy pillar at the time of providing the gas buffer area other than an inert gas in the 3rd layer in the said shower head. (A)-(d) is sectional drawing which shows the planar shape of the said dummy pillar. It is sectional drawing of the vertical direction which shows the shape of the said dummy pillar. It is sectional drawing which shows the structure of the semiconductor laser element manufactured with the said vapor phase growth apparatus. It is sectional drawing which shows the structure of the conventional vertical shower head type vapor phase growth apparatus. It is sectional drawing which shows the structure of the conventional vertical type shower head type vapor phase growth apparatus. It is the schematic which shows the whole structure of the other conventional vertical shower head type vapor phase growth apparatus. It is sectional drawing which shows the structure of the shower head in the conventional another vertical shower head type vapor phase growth apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Growth chamber 2 Reactor 3 Substrate to be deposited 4 Susceptor 5 Heater 7 Rotating shaft 10 MOCVD apparatus (vapor phase growth apparatus)
DESCRIPTION OF SYMBOLS 11 Gas discharge part 12 Purge line 20 Shower head 21 Shower plate 21a Center part 21b Peripheral part 22 Chilled water supply part 22b Chilled water system buffer area 23 III group gas supply part 23a III group gas outer ring flow path 23b III group gas buffer area (Second source gas intermediate chamber)
23c Group III gas supply pipe 24 Group V gas supply unit 24a Group V gas outer ring passage 24b Group V gas buffer area (first source gas intermediate chamber)
24c Group V gas supply pipe (first source gas pipe)
24d partition 25 with temperature adjustment mechanism (column heating means)
25c Dummy pillar (pillar)
26b Other gas buffer area 26c Other gas supply pipe 27b Other gas buffer area 41 Boundary plate 41a Boundary plate 42 Member with poor heat conduction 43 Dummy column 44 Dummy column 45 Dummy column 46 Dummy column 47 Dummy column 48 Dummy column 49 Fin 50 Semiconductor laser Element H Opening H3 Group III gas discharge hole H5 Group V gas discharge hole

Claims (15)

Growth that accommodates a deposition target substrate via a shower plate provided with a plurality of first source gas discharge holes and a plurality of second source gas discharge holes for independently discharging the first source gas and the second source gas, respectively. In the vapor phase growth apparatus for supplying the film into the chamber and mixing the film in the growth chamber to form the film formation substrate,
On the shower plate, a second source gas intermediate chamber and a first source gas intermediate chamber, which are separated from each other and filled with the second source gas and the first source gas, are stacked in this order,
The second source gas intermediate chamber is provided with a plurality of first source gas pipes penetrating from the first source gas intermediate chamber to the plurality of first source gas discharge holes of the shower plate,
In the first source gas intermediate chamber, a plurality of columns are provided in the same plane position as the plurality of second source gas discharge holes.   2. The vapor phase growth apparatus according to claim 1, further comprising a column heating unit configured to heat a plurality of columns in the first source gas intermediate chamber.   3. The vapor phase growth apparatus according to claim 2, wherein the first source gas intermediate chamber in which the plurality of columns are heated is provided in a layer farthest from the shower plate.   4. The vapor phase growth apparatus according to claim 1, wherein the plurality of columns in the first source gas intermediate chamber are made of a heat conductive material. 5.   The plurality of pillars in the first source gas intermediate chamber are made of a material having good thermal conductivity on the side opposite to the second source gas intermediate chamber, and the second source gas intermediate chamber side is in the second source gas intermediate chamber side. 4. The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus is made of a material having a lower thermal conductivity than the side opposite to the chamber.   The plurality of columns in the first source gas intermediate chamber are provided with gaps between the pillars and the second source gas intermediate chamber. The vapor phase growth apparatus according to item.   The vapor phase growth according to any one of claims 1 to 5, wherein the plurality of pillars in the first source gas intermediate chamber are tapered on a boundary plate side with the second source gas intermediate chamber. apparatus. The plurality of columns in the first source gas intermediate chamber are provided in the same plane position as the plurality of first source gas discharge holes with a gap between the boundary plate and the second source gas intermediate chamber. And
In the second source gas intermediate chamber, a gap is formed between the shower plate in the second source gas intermediate chamber or a boundary plate on the shower plate side at the same plane position as the plurality of second source gas discharge holes. The vapor phase growth apparatus according to claim 6, further comprising a plurality of columns.   9. The vapor phase growth apparatus according to claim 1, wherein the plurality of columns in the first source gas intermediate chamber have a polygonal cross-sectional shape perpendicular to the standing direction. .   The vapor phase growth apparatus according to claim 1, wherein the plurality of columns in the first source gas intermediate chamber have fins. The first source gas is a group V gas,
10. The vapor phase growth apparatus according to claim 1, wherein the second source gas is a group III-based gas.   The vapor phase growth apparatus according to claim 11, wherein the group V gas is a gas containing ammonia.   The plurality of first source gas discharge holes and the plurality of second source gas discharge holes each have a smaller hole diameter in the peripheral part of the shower plate than in the central part. The vapor phase growth apparatus described.   The inert gas discharge hole is provided in the said shower plate between the 1st source gas discharge hole and the 2nd source gas discharge hole, The any one of Claims 1-13 characterized by the above-mentioned. Vapor growth equipment.   A method for manufacturing a semiconductor element, wherein a semiconductor element is manufactured using the vapor phase growth apparatus according to claim 1.

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