JP5524280B2 - Vapor growth equipment - Google Patents

Description

  The present invention relates to a vapor phase growth apparatus.

  For the semiconductor light emitting device, a nitride semiconductor such as AlGaN or InGaN in which a part of a group III element is replaced with Al, In, or the like is used.

  When AlGaN is grown using metal organic chemical vapor deposition, reaction products that do not contribute to growth on the substrate are generated if Group III source gas and Group V source gas are mixed excessively in the apparatus. However, the Al composition is limited, and the in-plane uniformity and reproducibility of the composition and the film thickness are lowered. For this reason, a configuration is adopted in which the group III and group V source gases are separated and introduced to the vicinity of the substrate. For example, Patent Document 1 discloses a technique for introducing a source gas containing a group III source and a nitrogen source substantially in parallel with the substrate surface in a layered manner. Further, Patent Document 2 discloses a technique in which a through-hole for mixing a raw material gas is provided at the end of a partition plate of a vapor phase growth apparatus in order to make the vapor phase reaction more uniform.

  On the other hand, for example, in the growth of InGaN, it is desirable that the flow rate ratio of the group V source gas is high. , Turbulence occurs, and in-plane uniformity and reproducibility deteriorate. In the prior art, it is difficult to grow each of the semiconductor layers having different compositions under appropriate conditions.

JP 11-354456 A JP 2007-317770 A

  The present invention provides a vapor phase growth apparatus that can form semiconductor layers having different compositions with high in-plane uniformity and high reproducibility.

According to one aspect of the present invention, a vapor phase growth apparatus is provided for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas. The vapor deposition apparatus includes a reaction chamber in which the substrate is placed in communication with the reaction chamber, a first gas supply unit for supplying toward said group III material gas to the substrate, communicating with the reaction chamber and, a pre-Symbol V group material gas and a second gas supply unit for supplying toward the substrate. The first gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the first gas supply unit. It has the 1st mixing part supplied toward the side. The first gas supply unit further includes a first pipe into which the group III source gas is introduced. The first mixing unit is provided between the first pipe and the reaction chamber. A pipe into which the group V source gas is introduced is connected to the first pipe side of the first mixing unit. The first gas supply unit, a first operation and growing a first semiconductor layer of the group III material gas is supplied toward the substrate, the group III material gas is mixed in the first mixing section and The second group gas source gas is supplied toward the substrate and a second operation of growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer can be switched. is there.
According to another aspect of the present invention, there is provided a vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas. The vapor phase growth apparatus communicates with a reaction chamber in which the substrate is disposed, a first gas supply unit that supplies the group III source gas toward the substrate, and communicates with the reaction chamber. And a second gas supply unit that supplies the group V source gas toward the substrate. The first gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the first gas supply unit. It has the 1st mixing part supplied toward the side. The first gas supply unit communicates with the reaction chamber, communicates with the reaction chamber with a first supply pipe for supplying the group III source gas into the reaction chamber, and supplies the group V source gas into the reaction chamber. A second supply pipe for supplying. The first mixing part is a part inside the reaction chamber to which the first supply pipe and the second supply pipe are connected. The group III source gas and the group V source gas are mixed with each other on the first supply pipe and the second supply pipe side than the end of the first mixing part on the substrate side. The first gas supply unit supplies the group III source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the first mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. .
According to another aspect of the present invention, there is provided a vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas. The vapor phase growth apparatus communicates with a reaction chamber in which the substrate is disposed, a first gas supply unit that supplies the group V source gas toward the substrate, and communicates with the reaction chamber. And a second gas supply unit for supplying the group III source gas toward the substrate. The second gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the second gas supply unit. It has the 1st mixing part supplied toward the side. The second gas supply unit further includes a first pipe into which the group V source gas is introduced. The first mixing unit is provided between the first pipe and the reaction chamber. A pipe for introducing the group III source gas is connected to the first pipe side of the first mixing section. The second gas supply unit supplies the group V source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the first mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. .

  ADVANTAGE OF THE INVENTION According to this invention, the vapor phase growth apparatus which can form each of the semiconductor layer of a different composition with high in-plane uniformity and high reproducibility is provided.

It is a flowchart figure which shows a vapor phase growth method. It is a typical sectional view showing a semiconductor light emitting element. It is a schematic diagram which shows a vapor phase growth apparatus. FIG. 4A and FIG. 4B are schematic views showing a vapor phase growth method. It is a schematic diagram which shows the vapor phase growth method of a comparative example. It is a schematic diagram which shows a vapor phase growth apparatus. It is a flowchart figure which shows a vapor phase growth method. It is a flowchart figure which shows a vapor phase growth method. It is a schematic diagram which shows a vapor phase growth apparatus. FIG. 10A and FIG. 10B are schematic views showing a vapor phase growth method. It is a schematic diagram which shows a vapor phase growth apparatus. It is a schematic diagram which shows a vapor phase growth apparatus. FIG. 13A and FIG. 13B are schematic views showing a vapor phase growth method. It is a schematic diagram which shows a vapor phase growth apparatus. It is a schematic diagram which shows a vapor phase growth apparatus. It is a schematic diagram which shows a vapor phase growth apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
Note that, in the present specification and each drawing, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a flowchart illustrating the vapor phase growth method according to the first embodiment of the invention.
FIG. 2 is a schematic cross-sectional view illustrating the configuration of a semiconductor light emitting device manufactured using the vapor phase growth method and the vapor phase growth apparatus according to the first embodiment of the invention.
FIG. 3 is a schematic view illustrating the configuration of the vapor phase growth apparatus according to the first embodiment of the invention.

  First, an example of a semiconductor light emitting device manufactured using a vapor phase growth method and a vapor phase growth apparatus according to an embodiment of the present invention will be described with reference to FIG. The semiconductor light emitting element is, for example, a blue light emitting diode (LED), a white LED, a blue semiconductor laser (LD), or a blue-violet semiconductor LD. Hereinafter, a case where the semiconductor light emitting element is a blue LED will be described.

  As illustrated in FIG. 2, the semiconductor light emitting device 110 includes a buffer layer 101, an n-type contact layer 102, a light emitting layer 103, a p-type electron blocking layer 104, and a p-type contact layer 105 that are sequentially stacked on a substrate 90. It has a laminated structure including. For example, polycrystalline GaN is used for the buffer layer 101, and GaN doped with Si is used for the n-type contact layer 102, for example. The light emitting layer 103 has, for example, a quantum well structure in which a plurality of barrier layers and well layers are alternately stacked. For example, GaN is used for the barrier layer, and InGaN is used for the well layer, for example. For the p-type electron blocking layer 104, for example, AlGaN doped with Mg and having an Al composition of 15% can be used. As the p-type contact layer 105, GaN doped with Mg can be used.

  In the laminated structure of the semiconductor light emitting device 110, a part of the n-type contact layer 102 and a part of the light-emitting layer 103, the p-type electron blocking layer 104, and the p-type contact layer 105 are removed, and the n-type contact layer 102 is removed. A part of the contact layer 102 is exposed, and is connected to the n-side electrode 108 connected to the n-type contact layer 102, the p-side transparent electrode 106 connected to the p-type contact layer 105, and the p-side transparent electrode. Further, a p-side electrode 107 is further provided.

  As described above, the multilayer structure included in the semiconductor light emitting device using the nitride-based semiconductor is generally composed of AlGaN, InGaN, and GaN, and mixed crystals obtained by substituting a part of group III elements with Al and In. A semiconductor layer of AlInGaN is included. When forming such a stacked structure of semiconductor light emitting devices, for example, metal organic chemical vapor deposition (MOCVD) is used, and the type and flow rate of the source gas are controlled according to the composition of each semiconductor layer. Is done.

  In the semiconductor light emitting device 110 described above, the p-type electron blocking layer 104 (in the above example, AlGaN doped with Mg and having an Al composition of 15%) is nitrided with an Al composition ratio in group III of 10 atomic percent or more. This is a first semiconductor layer including a physical semiconductor. The well layer (InGaN in the above example) is a second semiconductor layer including a nitride-based semiconductor having an Al composition ratio in group III of less than 10 atomic percent.

  As described above, the semiconductor light emitting device 110 includes a first semiconductor layer including a nitride-based semiconductor having an Al composition ratio in Group III of 10 atomic percent or more, and a nitride having an Al composition ratio in Group III of less than 10 atomic percent. And a second semiconductor layer containing a system semiconductor.

  The vapor phase growth apparatus according to this embodiment can be used when growing the first and second semiconductor layers having different Al compositions on the substrate 90 as described above. This vapor phase growth apparatus is a vapor phase growth apparatus for growing a nitride-based semiconductor layer on a substrate 90 by vapor phase growth using a group III source gas and a group V source gas.

  As shown in FIG. 3, the vapor phase growth apparatus 210 according to this embodiment includes a reaction chamber 50 (for example, a flow channel) in which the substrate 90 is disposed, the first gas supply unit 10, and the second gas supply unit 20. And comprising. Further, the third gas supply unit 30 may be further included.

  The first gas supply unit 10 communicates with the reaction chamber 50 and supplies either one of the group III source gas and the group V source gas toward the substrate 90 disposed in the reaction chamber 50, and III A second operation of mixing the group source gas and the group V source gas and supplying them to the substrate 90 arranged in the reaction chamber 50 is performed by switching.

  Here, one of the group III source gas and the group V source gas is used as the first source gas. The other one of the group III source gas and the group V source gas is used as the second source gas. In the following description, it is assumed that the first source gas is a group III source gas and the second source gas is a group V source gas.

  The second gas supply unit 20 communicates with the reaction chamber 50, and either the group III source gas or the group V source gas (second source gas, group V source gas) is disposed in the reaction chamber 50. Supply toward the substrate 90.

Thus, the first gas supply unit 10 is arranged in the reaction chamber 50 with the operation mode for supplying the first source gas toward the substrate 90 and the mixed first source gas and second source gas. It is possible to operate in an operation mode supplied toward the substrate 90. On the other hand, the second gas supply unit 20 supplies the second source gas.
Further, the third gas supply unit 30 communicates with the reaction chamber 50 and can supply a gas for subflow for adjusting the gas flow toward the substrate 90.

The specific configuration of the vapor phase growth apparatus 210 will be further described.
The vapor phase growth apparatus 210 is an example having a horizontal reaction chamber. The reaction chamber 50 is, for example, a cylindrical flow channel having a square cross section. The axis of the cylinder of the reaction chamber 50 is arranged horizontally, for example. In the reaction chamber 50, a flow path for the source gas is formed. A susceptor 91 is provided on the bottom surface side of the reaction chamber 50, and a substrate 90 on which vapor phase growth is performed is placed on the upper surface of the susceptor 91. As the susceptor 91 rotates, the substrate 90 can also rotate.

  A heater 92 is provided below the susceptor 91, and the substrate 90 is heated by the heater 92 via the susceptor 91. The heater 92 is controlled by the heater control unit 93.

  A source gas to be described later is introduced from a gas introduction part 51 at one end of the reaction chamber 50, and the source gas flows toward the substrate 90 in a direction parallel to the surface of the substrate 90, for example. The raw material gas after the reaction is discharged from a gas discharge portion (not shown) provided on the opposite side.

  In this specific example, the gas introduction part 51 is divided into three by a partition plate. That is, the second gas introduction part 21, the first gas introduction part 11, and the third gas introduction part 31 are provided in this order from the lower side, which is the susceptor 91 side. A first partition plate 11 a is provided between the first gas introduction part 11 and the second gas introduction part 21, and a second partition is provided between the first gas introduction part 11 and the third gas introduction part 31. A plate 11b is provided.

  The 1st gas introduction part 11 encloses the space between the 1st partition plate 11a and the 2nd partition plate 11b. A gas is supplied from the first gas introduction unit 11 toward the substrate 90. The second gas introduction part 21 encloses the space between the first partition plate 11a and the second gas introduction part wall 21n. A gas is supplied from the second gas introduction unit 21 toward the substrate 90. The third gas introduction part 31 surrounds the space between the second partition plate 11b and the third gas introduction part wall 31n. A gas is supplied from the third gas introduction unit 31 toward the substrate 90. That is, the first gas supply unit 10 and the second gas supply unit 20 are separated from each other by the partition plate (first partition plate 11a). The first gas supply unit 10 and the third gas supply unit 30 are separated from each other by a partition plate (second partition plate 11b).

  The end portion 11ae of the first partition plate 11a is close to the susceptor 91, and the end portions of the first gas introducing portion 11 and the second gas introducing portion 21 are close to the substrate 90. Thereby, the gas supplied from the first gas introduction part 11 and the gas supplied from the second gas introduction part 21 are not mixed excessively with each other, and these gases are layered and appropriately separated. In this state, it is introduced toward the substrate 90.

  The end portion 11be of the second partition plate 11b is close to the susceptor 91, and the end portions of the first gas introducing portion 11 and the third gas introducing portion 31 are close to the substrate 90. Thereby, the gas supplied from the first gas introduction unit 11 and the gas supplied from the third gas introduction unit 31 are not mixed excessively with each other, and these gases are layered and appropriately separated. In this state, it is introduced toward the substrate 90.

  In the specific example shown in FIG. 3, the position along the gas introduction direction of the end portion 11ae of the first partition plate 11a and the position along the gas introduction direction of the end portion 11be of the second partition plate 11b are: Although the same, the relationship between the position of the end portion 11ae of the first partition plate 11a and the position of the end portion 11be of the second partition plate 11b is arbitrary. For example, the position along the gas introduction direction of the end portion 11be of the second partition plate 11b may be closer to the substrate 90 than the position along the gas introduction direction of the end portion 11ae of the first partition plate 11a.

  A second pipe 22 is connected to the second gas introduction part 21. For example, at least one of hydrogen gas and nitrogen gas is introduced into the second pipe 22 via, for example, a valve (not shown) and a mass flow controller (not shown). Accordingly, at least one of hydrogen gas and nitrogen gas is introduced into the second gas introduction unit 21 with the flow rate controlled.

Further, a second raw material gas pipe 23 is connected to the second pipe 22 via a second valve 23v and a second mass flow controller 23m. For example, an NH ₃ gas cylinder is connected to the side of the second source gas pipe 23 opposite to the second mass flow controller 23m. That is, the second source gas pipe 23 is supplied with the NH ₃ gas of the V group source gas which is the second source gas. As a result, the NH ₃ gas that is the second source gas (in this example, the V group source gas) is supplied to the second gas introduction unit 21 with the flow rate controlled.

  On the other hand, a first pipe 12 is connected to the first gas introduction part 11. For example, at least one of hydrogen gas and nitrogen gas is introduced into the first pipe 12 via, for example, a valve (not shown) and a mass flow controller (not shown). Accordingly, at least one of hydrogen gas and nitrogen gas is introduced into the first gas introduction unit 11 with the flow rate controlled.

  Further, the first raw material gas pipe 13 is connected to the first pipe 12 via the first valve 13v and the first mass flow controller 13m. For example, a pipe for introducing an organometallic gas of a group III source gas, which is a first source gas, is connected to the side of the first source gas pipe 13 opposite to the first mass flow controller 13m. That is, the first source gas pipe 13 is supplied with the organometallic gas of the group III source gas that is the first source gas.

  Further, a second source gas pipe for mixing 43 is connected to the first pipe 12 via a gas valve for mixing 43v and a gas mass flow controller for mixing 43m. The position where the second raw material gas pipe 43 for mixing is connected to the first pipe 12 is downstream of the position where the first raw material gas pipe 13 is connected to the first pipe 12. That is, the second source gas pipe 43 for mixing is connected to the first pipe 12 between the first source gas pipe 13 and the first gas introduction part 11. And in the 1st piping 12, the external mixing part 45 (mixing part) is provided between the 2nd raw material gas piping 43 for mixing and the 1st gas introduction part 11. As shown in FIG.

  As described above, the vapor phase growth apparatus 210 is a vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on the substrate 90 using a group III source gas and a group V source gas. A reaction chamber 50, which communicates with the reaction chamber 50, communicates with the first gas supply unit 10 which supplies either the group III source gas or the group V source gas toward the substrate, and the reaction chamber 50. A second gas supply unit 20 configured to supply the other of the group source gas and the group V source gas toward the substrate 90.

  Then, at least one of the first gas supply unit 10 and the second gas supply unit 20 (the first gas supply unit 10 in this specific example) mixes the group III source gas and the group V source gas, A mixing unit (this example) that supplies the mixed group III source gas and group V source gas toward the reaction chamber 50 side of at least one of the above gas supply units (first gas supply unit 10 in this example) In the example, it has an external mixing unit 45), and at least one of the gas supply units (in this example, the first gas supply unit 10) receives the group III source gas and the group V source gas mixed in the mixing unit. Further supply to the substrate 90 arranged in the reaction chamber 50 is possible.

  In this specific example, the mixing unit (external mixing unit 45) is provided in the first gas supply unit 10. And the 1st gas supply part 10 further has the 1st piping 12 in which either one of group III source gas and group V source gas (in this case III group source gas) is introduce | transduced. The mixing unit (external mixing unit 45) is provided between the first pipe 12 and the reaction chamber 50. A pipe (mixing first pipe) into which the other of the group III source gas and the group V source gas (in this case, the group V source gas) is introduced on the first pipe 12 side of the mixing section (external mixing section 45). Two source gas pipes 43) are connected.

  In the first pipe 12, when the first source gas is introduced from the first source gas pipe 13 without introducing the second source gas from the second source gas pipe 43 for mixing, A first source gas is introduced. That is, the group III source gas is introduced from the first gas introduction part 11. At this time, when the group V source gas is introduced from the second gas introduction unit 21, the group III source gas and the group V source gas are respectively supplied from different outlets (the first gas introduction unit 11 and the second gas introduction unit 21). Can be supplied.

  In the first pipe 12, when the second source gas is introduced from the second source gas pipe 43 for mixing while the first source gas is introduced from the first source gas pipe 13, The gas and the second source gas are mixed, and the mixed first source gas and second source gas are introduced into the first gas introduction unit 11. That is, the group III source gas and the group V source gas are supplied from the same outlet (first gas introduction unit 11). At this time, the second source gas (group V source gas) may be introduced from the second gas introduction part 21, thereby increasing the flow rate ratio of the group V source gas.

  The first gas supply unit 10 mixes the group III source gas and the group V source gas, and supplies the mixed group III source gas and group V source gas toward the reaction chamber 50 side of the first gas supply unit 10. The first gas supply unit 10 directs the group III source gas and the group V source gas mixed in the mixing unit toward the substrate 90 disposed in the reaction chamber 50. Further supply is possible.

  Thereby, in the vapor phase growth apparatus 210 of this specific example, the operation of introducing the first source gas (for example, the group III source gas) into the first gas introduction unit 11 and the mixing into the first gas introduction unit 11 are performed. Two different operations, that is, the operation of introducing the first source gas (for example, Group III source gas) and the second source gas (for example, Group V source gas), can be performed.

  In addition, the external mixing part 45 can have a chamber structure with a larger cross-sectional area than the 1st piping 12, for example. Thereby, the mixing efficiency of the first source gas and the second source gas is improved. However, the present invention is not limited to this, and the configuration of the external mixing unit 45 is arbitrary. For example, even when a pipe having the same diameter as the first pipe 12 is used as the external mixing unit 45, a sufficient mixing effect is obtained. It is done.

  A third pipe 32 is connected to the third gas introduction part 31. For example, at least one of hydrogen gas and nitrogen gas is introduced into the third pipe 32 via, for example, a valve (not shown) and a mass flow controller (not shown). Accordingly, at least one of hydrogen gas and nitrogen gas is introduced into the third gas introduction unit 31 with the flow rate controlled.

Furthermore, a third source gas pipe 33 is connected to the third pipe 32 via a third valve 33v and a third mass flow controller 33m. In this specific example, for example, a NH ₃ gas cylinder is connected to the side of the third source gas pipe 33 opposite to the third mass flow controller 33m. That is, the third source gas pipe 33 is supplied with NH ₃ gas which is a group V source gas. As a result, the NH ₃ gas that is the second source gas (in this example, the V group source gas) can also be supplied to the third gas introduction unit 31 with the flow rate controlled.

  In the vapor phase growth apparatus 210, an operation of introducing a first source gas (for example, a group III source gas) into the first gas introduction unit 11, and a first source gas mixed into the first gas introduction unit 11 ( For example, the operation of introducing a group III source gas) and a second source gas (for example, a group V source gas) can be performed, and the nitride-based semiconductor layer is grown by using these two operations separately. Can do.

  That is, the vapor phase growth apparatus 210 supplies the reaction chamber 50 in which the substrate 90 is disposed, and the group III source gas and the group V source gas from different outlets toward the substrate 90 disposed in the reaction chamber 50. Then, the operation of growing the first semiconductor layer including the nitride-based semiconductor having an Al composition ratio of 10 atomic percent or more in the group III, and the group III source gas and the group V source gas are mixed and from the same outlet, And a gas supply unit 80 for supplying the substrate 90 and growing a second semiconductor layer containing a nitride-based semiconductor having an Al composition ratio of less than 10 atomic percent in the group III.

Here, the gas supply unit 80 includes a first gas supply unit 10 and a second gas supply unit 20.
The first gas supply unit 10 includes a first gas introduction unit 11, a first pipe 12, a first valve 13v, a first mass flow controller 13m, a first source gas pipe 13, an external mixing unit 45, a mixing gas valve 43v, It includes a mixing gas mass flow controller 43m and a mixing second source gas pipe 43.
The second gas supply unit 20 includes a second gas introduction unit 21, a second pipe 22, a second valve 23v, a second mass flow controller 23m, and a second source gas pipe 23.

  That is, for example, the gas supply unit 80 communicates with the reaction chamber 50, and directs one of the group III source gas and the group V source gas (for example, group III source gas) toward the substrate 90 disposed in the reaction chamber 50. A first gas supply unit 10 that is switched between a first operation of supplying the first group gas and a second operation of mixing the group III source gas and the group V source gas and supplying them to the substrate 90 disposed in the reaction chamber 50; The second gas supply unit 20 communicates with the reaction chamber 50 and supplies one of the group III source gas and the group V source gas (for example, a group V source gas) toward the substrate 90 disposed in the reaction chamber 50. And can have.

The gas supply unit 80 can further include a third gas supply unit 30.
The third gas supply unit 30 includes a third gas introduction unit 31, a third pipe 32, a third valve 33v, a third mass flow controller 33m, and a third source gas pipe 33.

For example, by using such a vapor phase growth apparatus 210, the vapor phase growth method according to the present embodiment can be performed.
That is, as shown in FIG. 1, in the vapor phase growth method according to the present embodiment, the reaction chamber 50 is supplied with a group III source gas and a group V source gas from a plurality of outlets of a gas supply pipe provided in the reaction chamber. A vapor phase growth method in which a nitride-based semiconductor layer is formed on a substrate 90 disposed in a reaction chamber 50 by supplying a group III source gas and a group V source gas to different outlets (for example, First semiconductor layer (for example, including a nitride-based semiconductor having an Al composition ratio of 10 atomic percent or more in group III supplied from the first gas introduction unit 11 and the second gas introduction unit 21) toward the substrate 90 The step of growing the p-type electron blocking layer 104 (step S110) and the group III source gas and the group V source gas are mixed and supplied from the same outlet (for example, the first gas introduction unit 11) toward the substrate 90. Al composition ratio in group III is 10 Comprising second semiconductor layer including a nitride semiconductor of less than percent (e.g. InGaN well layer) growing a (step S120), the.

Then, the step of growing the second semiconductor layer (step S120) is performed using a group III source gas and a group V from an outlet (for example, the second gas inlet 21) different from the same outlet (first gas inlet 11). Either one of the source gases (for example, a group V source gas) can be further supplied toward the substrate 90. Thereby, for example, the flow rate ratio with respect to the total flow rate of the second source gas (for example, NH ₃ gas which is a group V source gas) can be increased.

  However, the present invention is not limited to this. In step S120, the group III source gas and the group V source gas are mixed and supplied from the same outlet (for example, the first gas introduction unit 11), and used in step S110. One of the group III source gas and the group V source gas (for example, group V source gas) is directed toward the substrate 90 from an outlet different from the two outlets (the first gas introduction unit 11 and the second gas introduction unit 21). Further, it may be supplied.

  Hereinafter, in step S110, the group III source gas and the group V source gas are respectively supplied from the first gas introduction unit 11 and the second gas introduction unit 21 which are different outlets, and in step S120, the group III source gas is supplied. As an example, the source gas and the group V source gas are mixed and supplied from the first gas introduction unit 11 that is the same outlet, and the group V source gas is supplied from the second gas introduction unit 21.

FIG. 4 is a schematic view illustrating a vapor phase growth method according to an embodiment of the invention.
4A corresponds to a step (step S110) of growing a first semiconductor layer containing a nitride-based semiconductor having an Al composition ratio of 10 atomic percent or more, and FIG. 4B shows an Al composition ratio. Corresponds to a step (step S120) of growing a second semiconductor layer containing a nitride-based semiconductor of less than 10 atomic percent.

  As illustrated in FIG. 4A, the first source gas g <b> 1 is supplied from the first gas introduction unit 11 toward the substrate 90 when the first semiconductor layer is grown. For example, trimethylaluminum (TMA), which is a group III source gas, is used for the first source gas g1.

Then, the second source gas g <b> 2 is supplied from the second gas introduction unit 21 toward the substrate 90. As the second source gas, ammonia (NH ₃ ), which is a group V source gas, is used.

Then, the third source gas g3 is supplied from the third gas introduction unit 31 toward the substrate 90. For example, N ₂ is used as the third source gas. The third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

  Since the 1st partition plate 11a is provided between the 1st gas introduction part 11 and the 2nd gas introduction part 21, the 1st source gas g1 and the 2nd source gas to the edge part 11ae of the 1st partition plate 11a g2 are separated from each other. The first source gas g1 and the second source gas g2 remain substantially separated after leaving the first gas introduction part 11 and the second gas introduction part 21, respectively, to the substrate 90 as a laminar flow gl. To reach. For this reason, it is difficult for reaction products to adhere to unnecessary portions other than the upper surface of the substrate 90. For this reason, in the 1st semiconductor layer to grow, the control range of Al composition is wide and it is easy to obtain the semiconductor layer of arbitrary Al composition. Since the source gas reaches the substrate 90 in a laminar flow gl, the in-plane uniformity of the composition of the first semiconductor layer and the film thickness of the first semiconductor layer is high. The composition of the first semiconductor layer and the reproducibility of the film thickness of the first semiconductor layer are also good.

On the other hand, as illustrated in FIG. 4B, when the second semiconductor layer is grown, the first source gas g <b> 1 and the second source gas g <b> 2 are mixed from the first gas introduction unit 11 to form the substrate 90. Supply towards For example, trimethylindium (TMI), which is a group III source gas, is used as the first source gas g1 at this time. Further, the group V source gas NH ₃ is used as the second source gas g2. That is, a mixed gas gm of the group III source gas TMI and the group V source gas NH 3 is supplied from the first gas introduction unit 11 toward the substrate 90.

Then, from the second gas inlet 21, as a second raw material gas g2, supplying NH ₃ gas as group V source gas.

Then, a third source gas g3 (for example, N ₂ ) is supplied from the third gas introduction unit 31. Also in this case, the third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

When growing the second semiconductor layer having a low Al composition ratio, it is desirable to increase the flow rate ratio of the NH ₃ gas to the total flow rate from the viewpoint of crystallinity and growth efficiency of the second semiconductor layer. In the vapor phase growth method and vapor phase growth apparatus 210 according to the present embodiment, the mixed gas gm of TMI and NH ₃ is supplied from the first gas introduction unit 11 while NH ₃ is supplied from the second gas introduction unit 21. it therefore becomes easy to increase the percentage of the total of the NH _3. For example, if the flow rate of NH ₃ supplied from the second gas introduction unit 21 is higher than that of other gas introduction units, turbulent flow may occur, but the flow rate of NH ₃ supplied from the second gas introduction unit 21 may be reduced. , By suppressing the generation of turbulent flow by suppressing to the same level as the other gas introducing portions, setting the flow rate so as not to generate turbulent flow, and supplying the mixed gas gm of TMI and NH ₃ from the first gas introducing portion 11, While maintaining the laminar flow gl, the flow rate ratio of the NH ₃ gas to the total flow rate can be increased.

Accordingly, the second semiconductor layer having a low Al composition ratio is grown by increasing the flow rate ratio of the NH ₃ gas, the in-plane uniformity of the composition and film thickness in the second semiconductor layer is increased, and the composition in the second semiconductor layer and The reproducibility of the film thickness can be increased.
As described above, according to the vapor phase growth method according to the present embodiment and the vapor phase growth apparatus 210 according to the present embodiment, the semiconductor layers having different compositions can be formed with high in-plane uniformity and high reproducibility.

FIG. 5 is a schematic view illustrating a vapor phase growth method of a comparative example.
As shown in FIG. 5A, in the vapor phase growth apparatus 218 of the first comparative example, the first gas introduction unit 11 supplies a first source gas (for example, TMA or TMI), and the second gas introduction unit. 21 introduces a second source gas (NH ₃ ). The method of the first comparative example corresponds to the method described in Patent Document 1. When the first semiconductor layer having a high Al composition ratio is grown, as described with reference to FIG. 4A, as in the vapor phase growth apparatus according to the present embodiment, generation of unnecessary reaction products is suppressed, One semiconductor layer can be grown.

However, in the vapor phase growth apparatus 218 of the first comparative example, when the flow rate of NH _{3 is} increased when growing the second semiconductor layer having a low Al composition ratio, the turbulent flow gt is generated. That is, for example, a turbulent flow gt is generated in the reaction chamber 50 due to the difference between the flow rate at the outlet of the second gas introduction unit 21 for supplying NH ₃ and the flow rate at the exit of the first gas introduction unit 11. For example, when the flow rate of the first gas introduction unit 11 with respect to the entire flow rate becomes 0.5 or more, the turbulent flow gt occurs.

  When the turbulent flow gt occurs, a concentration distribution of the source gas is generated on the surface of the substrate 90, and as a result, in-plane unevenness occurs in the composition and film thickness of the generated second semiconductor layer. In addition, the reproducibility of the composition and the film thickness also deteriorates. Further, the inner wall surface of the reaction chamber 50 is heated together with the substrate 90, and the reaction product easily adheres to that portion. The degree and history of reaction product adhesion change the temperature environment near the substrate, and the reproducibility of the semiconductor layer to be grown is lowered. In addition, if the reaction product is generated in a place other than the desired place, the utilization efficiency of the material is lowered, and maintenance of the vapor phase growth apparatus becomes difficult.

  As shown in FIG. 5B, in the vapor phase growth apparatus 219 of the second comparative example, the end portion 11ae of the first partition plate 11a between the first gas introduction portion 11 and the second gas introduction portion 21 is used. Is provided with a through hole 11ah in the first partition plate 11a. The device of the second comparative example corresponds to the device described in Patent Document 2. In this case, the first source gas g <b> 1 and the second source gas g <b> 2 are mixed with each other in stages near the end portions of the first gas introduction part 11 and the second gas introduction part 21. As a result, the composition and film thickness of the semiconductor layer grown on the substrate 90 may be made uniform in the plane of the substrate 90.

  However, since the configuration of the through-hole 11ah is the same both when growing the first semiconductor layer having a high Al composition ratio and when growing the second semiconductor layer having a low Al composition ratio, the first semiconductor layer and the second semiconductor layer It is difficult to grow under conditions optimal for both. For example, if the through hole 11ah is designed so as to be the optimum condition for the growth of the first semiconductor layer, the through hole 11ah is not the optimum condition for the growth of the second semiconductor layer.

In the vapor phase growth apparatus 219 provided with the through hole 11ah, the first source gas g1 and the second source gas g2 are always mixed by the through hole 11ah. When the first semiconductor layer having a high Al composition ratio is grown in a state where the first source gas g1 and the second source gas g2 are always mixed, the reaction product bp is easily generated at a place other than the substrate 90. Then, when the second semiconductor layer having a low Al composition ratio is grown in a state where the first source gas g1 and the second source gas g2 are always mixed, the second source gas supplied from the second gas introduction unit 11 is grown. It is necessary to increase the flow rate of (for example, NH ₃ ), and turbulent flow gt tends to occur. Thus, also in the vapor phase growth apparatus 219 of the second comparative example, it is difficult to grow both the first semiconductor layer and the second semiconductor layer under appropriate conditions.

In contrast, in the vapor phase growth method and the vapor phase growth apparatus 210 according to the present embodiment, when the first semiconductor layer having a high Al composition ratio is generated, the first source gas and the second source gas are separated. In this state, it is supplied toward the substrate 90. Thereby, the laminar flow gl can be realized in the growth of the first semiconductor layer. When the second semiconductor layer having a low Al composition ratio is grown, the first source gas and the second source gas are supplied from the first gas inlet 11 while the second source gas is supplied from the second gas inlet 21. The mixed gas gm can be supplied. Therefore, the flow rate of the second source gas supplied from the second gas introduction unit 21 is set to a relatively low flow rate that does not generate turbulent flow, and the mixed gas of the first source gas and the second source gas from the first gas introduction unit 11 By supplying gm, generation of turbulent flow can be suppressed, and the flow rate ratio of NH ₃ gas to the total flow rate can be increased while maintaining the laminar flow gl. That is, the laminar flow gl can be realized both when the first semiconductor layer is grown and when the second semiconductor layer is grown.

  In the vapor phase growth method and the vapor phase growth apparatus 210 according to the present embodiment, in the growth of the first semiconductor layer having a high Al composition ratio (step S110), the group III source gas and the group V source gas are: The first partition plate 11a is supplied separately up to the end 11ae. In the growth of the second semiconductor layer having a low Al composition ratio (step S120), the group III source gas and the group V source gas are upstream of the end portion 11ae of the first partition plate 11a (substrate 90). In the direction opposite to the direction towards). Thus, in step S110 and step S120, the state in which the source gas is separated up to the end of the first gas introduction unit 11 and the end of the second gas introduction unit 21, and the first gas introduction unit 11 Two types of states are used: a state in which the source gas is mixed before the end of the second gas introduction unit 21.

  On the other hand, in the first comparative example, the source gas is separated up to the end of the first gas introduction part 11 and the end of the second gas introduction part 21 in any state. On the other hand, in the second comparative example, the source gas is mixed before the end portions of the first gas introduction part 11 and the second gas introduction part 21 in any state.

Thus, in the present embodiment, the above two types of states are realized.
Thus, in the growth of the first semiconductor layer having a high Al composition ratio (step S110), the group III source gas and the group V source gas are separated to the vicinity of the substrate 90 and directed toward the substrate 90 in the reaction chamber 50. Therefore, the gas phase reaction between TMA and NH ₃ can be suppressed, so that the in-plane uniformity and reproducibility of the composition ratio and film thickness in the first semiconductor layer can be ensured.

Furthermore, in the growth (step S120) of a second semiconductor layer (eg, a semiconductor layer containing In) that has a low Al composition ratio, for example, Al, the flow rate ratio of NH ₃ with respect to the total flow rate is increased, and the group III material By mixing and supplying the gas and the group V source gas toward the substrate 90, the turbulent flow gt is suppressed and the laminar flow gl is maintained, so that the substrate surface having the composition ratio and the film thickness in the second semiconductor layer is maintained. Inner uniformity and reproducibility can be ensured.

  Then, by using the vapor phase growth apparatus 210 according to the present embodiment, the above steps S110 and S120 can be executed as a series of operations. Therefore, in both the first semiconductor layer and the second semiconductor layer, in-plane uniformity and reproducibility can be ensured at the same time, and a light-emitting element having excellent characteristics can be manufactured with high yield.

  Thus, in-plane uniformity of the composition ratio and film thickness can be improved in both the first semiconductor layer and the second semiconductor layer. Further, in both the growth of the first semiconductor layer and the second semiconductor layer, it is possible to suppress the generation of a reaction product in a portion other than the substrate 90, and to suppress the influence of environmental changes in the reaction chamber 50. Reproducibility can be maintained over the long term. Thus, each of the semiconductor layers having different compositions can be formed with high in-plane uniformity and high reproducibility.

  In the vapor phase growth method and vapor phase growth apparatus 210 according to the present embodiment, any gas containing a compound containing a group III element can be used as the group III source gas. As the group V source gas, any gas containing a compound containing a group V element can be used.

  For example, the group III source gas (for example, the first source gas) is at least one selected from the group consisting of trimethylaluminum, triethylaluminum, dimethylaluminum hydride, ethyldimethylamine alane, triisobutylaluminum, trimethylindium, and triethylindium. Can be included.

  Further, the group V source gas (for example, the second source gas) can include at least one selected from the group consisting of ammonia, monomethyl hydrazine, and dimethyl hydrazine.

Further, the group III source gas (for example, the first source gas) and the group V source gas (for example, the second source gas) can further include an arbitrary dopant gas that becomes a dopant included in the semiconductor layer to be grown. As such a dopant gas, for example, a monosilane (SiH ₄ ) gas serving as an n-type dopant can be used. Further, for example, biscyclopentadienyl magnesium (Cp ₂ Mg) and bismethylcyclopentadienyl magnesium (M ₂ Cp ₂ Mg) which are p-type dopants can be used.

(First embodiment)
Hereinafter, as a first example of a vapor phase growth method and a vapor phase growth apparatus 210 according to an embodiment of the present invention, an example of a method for manufacturing a semiconductor light emitting device 110 (blue light emitting diode) using a nitride semiconductor will be described. .

  First, the substrate 90 is placed on the susceptor 91. For the substrate 90, for example, sapphire is used. Next, the hydrogen gas is introduced from each of the first gas introduction unit 11, the second gas introduction unit 21, and the third gas introduction unit 31, for example, at a flow rate of 10 L (liter) / min. At a pressure of 500 Torr. Next, the substrate 90 is heated to, for example, 1100 ° C. by the heater 92 and held for 10 minutes.

Next, the temperature of the substrate 90 is set to 500 ° C., and nitrogen gas is introduced from the third gas introduction unit 31 at a flow rate of 10 L / min. Furthermore, hydrogen gas containing trimethylgallium (TMG) gas, which is the first source gas (Group III source gas), is introduced from the first gas introduction unit 11 at a flow rate of 10 L / min. Further, NH ₃ gas having a flow rate of 7 L / min and hydrogen gas having a flow rate of 3 L / min are introduced from the second gas introduction unit 21. Thereby, the buffer layer 101 of polycrystalline GaN is grown on the substrate 90.

Next, the introduction of the TMG gas supplied from the first gas introduction unit 11 is stopped, and the temperature of the substrate 90 is raised to 1050 ° C.
Thereafter, nitrogen gas is introduced from the third gas introduction unit 31 at a flow rate of 10 L / min, hydrogen gas containing TMG gas and monosilane gas is introduced from the first gas introduction unit 11 at a flow rate of 10 L / min, An NH ₃ gas having a flow rate of 7 L / min and a hydrogen gas having a flow rate of 3 L / min are introduced from the 2-gas introduction portion 21 to grow the n-type contact layer 102 containing GaN doped with Si.

Next, the introduction of the TMG gas and the monosilane gas introduced from the first gas introduction unit 11 is stopped, and the temperature of the substrate 90 is set to 780 ° C.
Thereafter, NH ₃ gas with a flow rate of 7 L / min and nitrogen gas with a flow rate of 3 L / min are introduced from the third gas introduction unit 31, and a flow rate of ₃ L / min from the first gas introduction unit 11, and nitrogen gas containing TMG gas, and NH ₃ gas of 7L / min flow rate, was introduced and the NH ₃ gas and 3L / min flow rate of nitrogen gas of 7L / min flow rate from the second gas inlet 21 Introduce and grow a barrier layer containing GaN. The thickness of the barrier layer is, for example, 5 nm (nanometer).

Subsequently, trimethylindium (TMI) gas is further introduced into the nitrogen gas of the first gas introduction unit 11. That is, NH ₃ gas with a flow rate of 7 L / min and nitrogen gas with a flow rate of 3 L / min are introduced from the third gas introduction unit 31, and a flow rate of ₃ L / min from the first gas introduction unit 11, nitrogen gas containing a TMG gas and TMI, 7L / min flow rate and NH ₃ gas, introduced, 7L from the second gas inlet 21 / min flow rate NH ₃ gas and 3L / min flow rate of nitrogen Introduce gas. As a result, a well layer containing GaInN having an In composition of 15% (15% atomic percent) in group III is grown to a thickness of 2.5 nm.

  Thereafter, the combination of the barrier layer and the well layer is further grown a total of seven times, and then further grown on the same condition as above. Thereby, the light emitting layer 103 having a multiple quantum well structure is formed.

In the formation of the barrier layer and the well layer, the flow rate ratio to the total flow rate of NH ₃ gas is as high as 0.7, but there are three gas introduction parts 51 (first, second, and third gas introduction parts). 11, 21, and 31), and the ratio of the flow rates of the gases introduced from the respective gas introduction portions (the first, second, and third gas introduction portions 11, 21, and 31) are substantially equalized. Yes. Thereby, in the gas introduced from the 1st, 2nd and 3rd gas introducing | transducing parts 11, 21, and 31, the turbulent flow gt of a gas flow does not generate | occur | produce, but the stable laminar flow gl is obtained.

Next, the introduction of the TMG gas and the TMI gas introduced from the first gas introduction unit 11 is stopped, and the temperature of the substrate 90 is raised to 1000 ° C.
Thereafter, nitrogen gas at a flow rate of 10 L / min is introduced from the third gas introduction unit 31, and hydrogen gas containing TMG gas, TMA gas and Cp ₂ Mg gas is flowed from the first gas introduction unit 11 at a flow rate of 10 L / min. Then, NH ₃ gas having a flow rate of 5 L / min and hydrogen gas having a flow rate of 5 L / min are introduced from the second gas introducing portion 21 to grow the p-type electron block layer 104. The p-type electron blocking layer 104 is AlGaN doped with Mg and having an Al composition of 15%. Here, the group III source gas containing TMA introduced from the first gas introduction unit 11 and the NH ₃ gas introduced from the second gas introduction unit 21 are discharged from the first partition plate 11a (first gas introduction). Are separated from each other up to the outlet of the part 11 and the outlet of the second gas introduction part 21, and are supplied from different outlets. These gases become a laminar flow gl and are supplied toward the substrate 90. Thus, the gas phase reaction between TMA gas and NH ₃ gas can be suppressed.

  Next, the introduction of the TMA gas introduced from the first gas introduction part 11 is stopped, the state of other gases is maintained, and the p-type contact layer 105 is grown. The p-type contact layer 105 is GaN doped with Mg.

  Next, the substrate 90 after the growth is taken out, and the p-side transparent electrode 106, the p-side electrode 107, and the n-side electrode 108 are formed, and the semiconductor light emitting device 110 is manufactured.

The characteristics of the semiconductor light emitting device 110 according to the vapor phase growth method of the first embodiment and the semiconductor light emitting device according to the following first comparative example will be described.
In the method of the first comparative example, when the barrier layer of the light emitting layer 103 is grown, nitrogen gas is introduced from the third gas introduction unit 31 at a flow rate of 4 L / min, and TMG gas is introduced from the first gas introduction unit 11. The contained nitrogen gas is introduced at a flow rate of 4 L / min, and NH ₃ gas at a flow rate of 21 L / min and nitrogen gas at a flow rate of 1 L / min are introduced from the second gas introduction unit 21. When the well layer of the light emitting layer 103 is grown, nitrogen gas is introduced from the third gas introduction unit 31 at a flow rate of 4 L / min, and nitrogen containing TMG gas and TMI gas is introduced from the first gas introduction unit 11. Gas is introduced at a flow rate of 4 L / min, and NH ₃ gas at a flow rate of 21 L / min and nitrogen gas at a flow rate of 1 L / min are introduced from the second gas introduction unit 21. Except this, the same conditions as in the first embodiment are used.

  The semiconductor light emitting device 110 according to the first example and the semiconductor light emitting device according to the first comparative example are both blue LEDs. A plurality of semiconductor light emitting elements are formed on the 2-inch substrate surface by the method of the first embodiment and the method of the first comparative example. The characteristics of the light emission output in the substrate surface at this time are as follows.

  In the semiconductor light emitting device according to the first comparative example, the light emission output is, for example, 85% or less at the outer peripheral portion of the substrate 90 as compared to the center of the substrate 90, and the light output is reduced at the outer peripheral portion of the substrate 90. On the other hand, in the semiconductor light emitting device 110 according to the first example, the variation in the light emission output is within a range of, for example, ± 5% within the plane of the substrate 90, and uniform light emission within the plane of the substrate 90 is achieved. can get. The average value of the light emission output in the plane of the substrate 90 is 10% or more larger in the semiconductor light emitting device 110 according to the first example than in the semiconductor light emitting device according to the first comparative example.

  As described above, according to the vapor phase growth method and the vapor phase growth apparatus 210 according to the present embodiment, semiconductor layers having different compositions (for example, the p-type electron block layer 104 as the first semiconductor layer, and the second semiconductor layer). Each of the well layers of the light emitting layer 103 can be formed with high in-plane uniformity and high reproducibility, and the semiconductor light emitting device 110 manufactured thereby has a light emission output in the substrate plane higher than that in the first comparative example. The variation is small, and the average value of the light emission output is high. Thus, according to the present embodiment, it is possible to obtain high characteristics with a high yield.

(Second Embodiment)
FIG. 6 is a schematic view illustrating the configuration of a vapor phase growth apparatus according to the second embodiment of the invention. FIG. 7 is a flowchart illustrating the vapor phase growth method according to the second embodiment of the invention.
As illustrated in FIG. 6, the vapor phase growth apparatus 211 according to the present embodiment further includes a measurement unit 60 and a control unit 70 with respect to the vapor phase growth apparatus 210 according to the first embodiment.

In this specific example, the measurement unit 60 is provided outside the reaction chamber 50 and above the susceptor 91 (above the surface on which the substrate 90 is placed).
The measuring unit 60 measures the optical characteristics of the surface of the substrate 90 (for example, the second semiconductor layer) during the growth of the second semiconductor layer.
Based on at least one of the temperature of the substrate 90 derived from the optical characteristics measured by the measurement unit 60, the growth rate of the second semiconductor layer, and the composition of the second semiconductor layer, the control unit 70 The mixing ratio of the gas and the group V source gas is controlled.

  The measurement unit 60 measures the optical characteristics of the first semiconductor layer during the growth of the first semiconductor layer, and the control unit 70 calculates the temperature of the substrate 90 derived from the optical characteristics measured by the measurement unit 60, Based on at least one of the growth rate of the first semiconductor layer and the composition of the first semiconductor layer, at least one of the flow rate of the group III source gas and the flow rate of the group V source gas may be further controlled.

  That is, the measurement unit 60 measures the optical characteristics of the substrate 90 during the growth of the nitride-based semiconductor layer grown on the substrate 90. For example, the measurement unit 60 measures light emitted from the surface of the substrate 90 (or the susceptor 91) while forming a film, and measures the temperature of the substrate 90. The measurement unit 60 irradiates the surface of the substrate 90 (the nitride-based semiconductor layer formed) with light, measures the change in reflectance of the irradiated light, and forms the nitride-based semiconductor formed. Measure the growth rate of the layer. The measurement unit 60 measures the composition of the mixed crystal in the nitride-based semiconductor layer that is formed based on the reflection spectrum of the irradiated light.

  The optical monitor optical path 61 when the optical characteristic is measured by the measurement unit 60 passes through a window portion (not shown) of the reaction chamber 50. Thereby, the measurement unit 60 simultaneously measures the growth state of the semiconductor layer on the substrate 90 from the outside of the reaction chamber 50 while growing.

  The measurement result of the optical characteristics by the measurement unit 60 is output to the control unit 70 via the measurement data signal line 62. Then, the mixing control signal output from the controller 70 is output to the mixing gas mass flow controller 43m via the mixing control signal line 71. Further, the first control signal output from the control unit 70 is output to the first mass flow controller 13 m via the first control signal line 72. The heater control signal output from the control unit 70 is output to the heater control unit 93 via the heater control signal line 73.

  Thus, in the vapor phase growth apparatus 211, the substrate temperature, the growth rate of the semiconductor layer, and the mixed crystal composition of the semiconductor layer are measured in situ outside the reaction chamber 50 on the side facing the upper surface of the substrate 90. The measuring unit 60 is provided, and the control unit 70 controls the mass flow controller (mixing gas mass flow controller 43m and first mass flow controller 13m) and the heater control unit 93.

  For example, the control unit 70, for example, a group III introduced from the first gas introduction unit 11 based on measurement data of at least one of the substrate temperature, the growth rate, and the mixed crystal composition during the growth of the second semiconductor layer. The mixing ratio in the source gas and the group V source gas is changed.

  For example, when the In composition in the second semiconductor layer is lower than the target composition based on the above characteristics measured during the growth of the second semiconductor layer, the control unit 70 starts from the first gas introduction unit 11. Control is performed to relatively increase the ratio of the group V source gas in the mixed gas of the group III source gas and the group V source gas introduced.

  As described above, the characteristics of the semiconductor layer are optically measured by the measuring unit 60 during the growth of the semiconductor layer, and the mixing ratio of the group III source gas and the group V source gas is changed. The influence of the reaction product can be corrected and the reproducibility in the grown film can be further improved.

  That is, as shown in FIG. 7, in the vapor phase growth method according to the present embodiment, the step of growing the second semiconductor layer (step S120) is during the growth of the second semiconductor layer (nitride-based semiconductor layer). And measuring the optical characteristics of the second semiconductor layer (step S121), the temperature of the substrate 90 derived from the measurement result of the optical characteristics, the growth rate of the second semiconductor layer, and the composition of the second semiconductor layer. The step of controlling the mixing ratio of the group III source gas and the group V source gas (step S122) can be included. By using the vapor phase growth method according to the present embodiment, the reproducibility of the grown semiconductor layer can be further improved.

  That is, the degree and history of the reaction product attached to the vicinity of the substrate 90 in the reaction chamber 50 may change the temperature environment of the vicinity of the substrate 90 and may reduce the reproducibility of the semiconductor layer to be grown. By using the vapor phase growth method and the vapor phase growth apparatus 211 according to this embodiment, it is possible to suppress a decrease in reproducibility and manufacture a semiconductor light emitting device with excellent reproducibility in the long term.

(Second embodiment)
FIG. 8 is a flowchart illustrating the vapor phase growth method according to the second example of the second embodiment of the present invention.
That is, this figure is an example of control using the measurement unit 60 in the step of growing the second semiconductor layer containing In using the vapor phase growth apparatus 211 (step S120).

  The measured value of the growth rate of the second semiconductor layer is compared with the standard value (step S211), and the group III source gas is adjusted so that the difference between the measured value of the growth rate of the second semiconductor layer and the standard is within 5%. Is controlled (step S212). For example, the group III source gas flow rate is set to “current set flow rate” × “standard value of growth rate” / “measured value of growth rate”.

  Then, the measured value of the composition ratio (in this case, the composition ratio of In) in the second semiconductor layer is compared with the standard value (set value) (step S221). Further, it is determined whether or not the measured value of the composition ratio in the second semiconductor layer is higher than the standard value (step S222). If the measured value of the composition ratio is lower than the standard value, the group III source gas and The mixing ratio of the group V source gas in the mixing of the group V source gas is increased (step S224). When the measured value of the composition ratio is higher than the standard value, the mixing ratio of the group V source gas in the mixing of the group III source gas and the group V source gas is decreased (step S223). In addition, when the measured value of the composition ratio substantially matches the standard value, the mixing ratio is not changed.

For example, during the growth of the second semiconductor layer, the In composition ratio is measured (step S121), the measured value is compared with the standard value, and when the measured value is 5% or more lower than the standard value, the first gas The flow rate of NH ₃ gas (V group source gas) introduced into the introduction unit is increased by, for example, 5% from the current set value, and the mixing ratio of the V group source gas is increased. When the measured value of the In composition ratio is 5% or more higher than the standard value, the flow rate of the NH ₃ gas introduced into the first gas introduction unit is reduced by, for example, 5% from the current set value, and the group V Increase the mixing ratio of source gases. And step S221-step S224 are repeatedly implemented.

  In this specific example, the temperature of the substrate 90 is controlled by controlling the heater 92 by PID control based on the measured temperature of the substrate 90 (step S201), and the second semiconductor layer is grown. .

  As a result, a decrease in reproducibility of the semiconductor layer to be grown can be suppressed, and a semiconductor light emitting device can be manufactured with excellent reproducibility over the long term.

(Third embodiment)
FIG. 9 is a schematic view illustrating the configuration of a vapor phase growth apparatus according to the third embodiment of the invention. As shown in FIG. 9, in the vapor phase growth apparatus 212 according to this embodiment, the first pipe 12 and the mixing pipe 42 are connected to the first gas introduction section 11 of the first gas supply section 10. Yes. And the external mixing part 45 is not provided. The other parts of the second gas supply unit 20, the third gas supply unit 30, the reaction chamber 50, and other configurations are the same as those of the vapor phase growth apparatus 211 according to the second embodiment, and thus the description thereof is omitted.

  For example, at least one of hydrogen gas and nitrogen gas is introduced into the first pipe 12, and further, the first raw material gas is introduced into the first pipe 12 through the first valve 13v and the first mass flow controller 13m. A pipe 13 is connected. One of a group III source gas and a group V source gas (for example, a first source gas that is a group III source gas) is introduced into the first source gas pipe 13.

  The mixing second raw material gas pipe 43 is connected to the mixing pipe 42 via a mixing gas valve 43v and a mixing gas mass flow controller 43m. One of the group III source gas and the group V source gas (for example, the second source gas that is a group V source gas) is introduced into the second source gas pipe 43 for mixing.

  If both the first source gas and the second source gas are introduced into the first gas introduction part 11, on the upstream side (the direction opposite to the direction toward the substrate 90) from the end part 11ae of the first partition plate 11a, These gases are mixed. Thereby, step S120 for growing the second semiconductor layer can be performed. That is, the first gas introduction part 11 serves as an internal mixing part 11i for mixing the group III source gas and the group V source gas.

  If only the first source gas is introduced into the first gas introduction unit 11, the first source gas can be introduced in a state separated from the second source gas introduced from the second gas introduction unit 21, thereby Step S110 for growing one semiconductor layer can be performed.

  As described above, the first gas supply unit 10 communicates with the reaction chamber 50, and either one of the group III source gas and the group V source gas (for example, the first source gas which is a group III source gas) is supplied into the reaction chamber 50. The first supply pipe (first pipe 12) supplied to the reaction chamber 50 is communicated with the reaction chamber 50 to react either the group III source gas or the group V source gas (for example, the second source gas which is a group V source gas). And a second supply pipe (mixing pipe 42) for supplying the inside of the chamber 50. The mixing unit (internal mixing unit 11 i) is a part inside the reaction chamber 50 where the first supply pipe and the second supply pipe are connected. Then, the group III source gas and the group V source gas are mixed with each other in the internal mixing portion 11i that is closer to the first supply pipe and the second supply pipe than the end on the substrate 90 side (for example, the first end 11ae). Is done. Then, the mixed group III source gas and group V source gas are supplied toward the substrate 90 from the same outlet (first gas introduction portion 11).

  The vapor phase growth apparatus 212 having such a configuration also supplies the group III source gas and the group V source gas from different outlets toward the substrate 90 disposed in the reaction chamber 50, and thereby adds Al in the group III. The operation of growing the first semiconductor layer containing a nitride-based semiconductor having a composition ratio of 10 atomic percent or more and the group III source gas and the group V source gas are mixed and supplied from the same outlet toward the substrate 90. And an operation of growing a second semiconductor layer containing a nitride-based semiconductor having an Al composition ratio in group III of less than 10 atomic percent.

(Fourth embodiment)
FIG. 10 is a schematic view illustrating a vapor phase growth method according to the fourth embodiment of the invention.
That is, FIG. 10A corresponds to a step (step S110) of growing a first semiconductor layer containing a nitride-based semiconductor having an Al composition ratio of 10 atomic percent or more, and FIG. 10B shows an Al composition ratio. Corresponds to a step (step S120) of growing a second semiconductor layer containing a nitride-based semiconductor of less than 10 atomic percent.

  As shown in FIG. 10A, when the first semiconductor layer is grown, the first source gas g <b> 1 is supplied from the first gas introduction unit 11 toward the substrate 90. For example, trimethylaluminum (TMA), which is a group III source gas, is used for the first source gas g1.

Then, the second source gas g <b> 2 is supplied from the second gas introduction unit 21 toward the substrate 90. As the second source gas, ammonia (NH ₃ ), which is a group V source gas, is used.

Then, the third source gas g3 is supplied from the third gas introduction unit 31 toward the substrate 90. For example, N ₂ is used as the third source gas. The third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

  Also in this case, the first source gas g1 and the second source gas g2 are separated from each other up to the end portion 11ae of the first partition plate 11a, and after exiting the first gas introduction portion 11 and the second gas introduction portion 21, respectively. However, the separated state is substantially maintained, and reaches the substrate 90 as a laminar flow gl. As a result, the reaction product hardly adheres to unnecessary portions other than the upper surface of the substrate 90, and the control range of the Al composition is wide in the first semiconductor layer to be grown, and a semiconductor layer having an arbitrary Al composition is easily obtained. Since the source gas reaches the substrate 90 in a laminar flow gl, the in-plane uniformity of the composition of the first semiconductor layer and the film thickness of the first semiconductor layer is high. The composition of the first semiconductor layer and the reproducibility of the film thickness of the first semiconductor layer are also good.

Then, as shown in FIG. 10B, during the growth of the second semiconductor layer, NH ₃ gas that is a group V source gas is supplied from the first gas introduction unit 11 as the second source gas g2. Is done.

Then, the first source gas g 1 and the second source gas g 2 are mixed and supplied from the second gas introduction unit 21 toward the substrate 90. For example, trimethylindium (TMI) and TMG, which are group III source gases, are used as the first source gas g1 at this time. Further, the group V source gas NH ₃ is used as the second source gas g2. That is, the mixed gas gm of the group III source gas TMI and the group V source gas NH ₃ is supplied from the second gas introduction unit 21 toward the substrate 90.

Then, a third source gas g3 (for example, N ₂ ) is used from the third gas introduction part 31. Also in this case, the third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

Thus, since the mixed gas gm of TMI and TMG and NH ₃ can be supplied from the second gas introduction unit 21 while supplying NH ₃ from the first gas introduction unit 11, the ratio of the entire NH ₃ is increased. Becomes easier. That is, the flow rate of NH ₃ supplied from the first gas introduction unit 11 is suppressed to the same level as the other gas introduction units so that no turbulent flow is generated, and the TMI, TMG, NH ₃ , By supplying the mixed gas gm, it is possible to suppress the generation of turbulent flow and increase the flow rate ratio of the NH ₃ gas to the total flow rate while maintaining the laminar flow gl. Accordingly, the second semiconductor layer having a low Al composition ratio is grown by increasing the flow rate ratio of the NH ₃ gas, the in-plane uniformity of the composition and film thickness in the second semiconductor layer is increased, and the composition in the second semiconductor layer and The reproducibility of the film thickness can be increased.

As described above, the vapor phase growth method according to the present embodiment also allows the group III source gas and the group V source gas to be directed toward the substrate 90 from different outlets (the first gas introduction unit 11 and the second gas introduction unit 21). A step of supplying and growing the first semiconductor layer (step S110), a group III source gas and a group V source gas are mixed and supplied from the same outlet (second gas introduction unit 21) toward the substrate. And a step of growing the second semiconductor layer (step S120). In this case as well, step S120 is performed using either the group III source gas or the group V source gas (in this case, the group V source material) from the outlet (first gas introduction unit 11) different from the same outlet. Gas) is further supplied toward the substrate 90.
According to the vapor phase growth method according to the present embodiment, each of the semiconductor layers having different compositions can be formed with high in-plane uniformity and high reproducibility.

Such a vapor phase growth method can be carried out by using, for example, the following vapor phase growth apparatus.
FIG. 11 is a schematic view illustrating the configuration of a vapor phase growth apparatus according to the fourth embodiment of the invention.
As shown in FIG. 11, also in the vapor phase growth apparatus 220 according to the present embodiment, the gas introduction unit 51 is divided into three by a partition plate, and the second gas introduction unit 21, the second gas introduction unit 51 are divided into three. The 1 gas introduction part 11 and the 3rd gas introduction part 31 are provided.

  The first gas supply unit 10 and the second gas supply unit 20 are separated from each other by a partition plate (first partition plate 11a). The first gas supply unit 10 and the third gas supply unit 30 are separated from each other by a partition plate (second partition plate 11b).

  A second pipe 22 is connected to the second gas introduction part 21. For example, at least one of hydrogen gas and nitrogen gas is introduced into the second pipe 22 via, for example, a valve (not shown) and a mass flow controller (not shown). Accordingly, at least one of hydrogen gas and nitrogen gas is introduced into the second gas introduction unit 21 with the flow rate controlled.

Further, a second raw material gas pipe 23 is connected to the second pipe 22 via a second valve 23v and a second mass flow controller 23m. For example, an NH ₃ gas cylinder is connected to the side of the second source gas pipe 23 opposite to the second mass flow controller 23m. That is, the second source gas pipe 23 is supplied with the NH ₃ gas of the V group source gas which is the second source gas. As a result, the NH ₃ gas that is the second source gas (in this example, the V group source gas) is supplied to the second gas introduction unit 21 with the flow rate controlled.

The first raw material gas pipe 13 is connected to the side of the second pipe 22 opposite to the side connected to the reaction chamber 50 via the second distribution valve 15v and the first valve 13v.
An external mixing unit 45 a (mixing unit) is provided between the second valve 23 v of the second pipe 22 and the reaction chamber 50.

Thereby, in one operation state, the second source gas g2 (for example, NH ₃ gas) can be introduced into the second gas introduction unit 21 via the second source gas pipe 23. Then, the second source gas g <b> 2 is supplied from the second gas introduction unit 21 toward the substrate 90.

  Further, in another operating state, the first source gas g1 is introduced into the mixing unit 45a from the first source gas pipe 13, and at the same time, the second source gas g2 from the second source gas pipe 23 is introduced into the mixing unit 45a. Is introduced, and the mixed first source gas g1 and second source gas g2 are introduced into the second gas introduction part 21. Then, the mixed first source gas g1 and second source gas g2 are supplied from the second gas introduction part 21 toward the substrate 90.

  On the other hand, a first pipe 12 is connected to the first gas introduction part 11. For example, at least one of hydrogen gas and nitrogen gas is introduced into the first pipe 12 via, for example, a valve (not shown) and a mass flow controller (not shown). Accordingly, at least one of hydrogen gas and nitrogen gas is introduced into the first gas introduction unit 11 with the flow rate controlled.

  Further, the first raw material gas pipe 13 is connected to the first pipe 12 via a first distribution valve 14v, a first valve 13v, and a first mass flow controller 13m. For example, a pipe for introducing an organometallic gas of a group III source gas, which is a first source gas, is connected to the side of the first source gas pipe 13 opposite to the first mass flow controller 13m. That is, the first source gas pipe 13 is supplied with the organometallic gas of the group III source gas that is the first source gas.

  Further, a second source gas pipe for switching 44 is connected to the first pipe 12 via a switching gas valve 44v and a switching gas mass flow controller 44m. In this specific example, the position where the switching second source gas pipe 44 is connected to the first pipe 12 is upstream of the position where the first source gas pipe 13 is connected to the first pipe 12.

  Thus, in one operating state, the second source gas g2 is not supplied from the second source gas pipe 44 for switching, and the first gas introduction unit 11 is connected to the first source gas pipe 13 via the first source gas pipe 13. A source gas g1 (for example, a group III source gas) can be introduced. Then, the first source gas g <b> 1 is supplied from the first gas introduction unit 11 toward the substrate 90.

Further, in another operating state, the supply of the first raw material gas g1 from the first raw material gas pipe 13 is stopped, and the first gas introduction unit 11 is connected to the first raw material gas pipe 44 via the switching second raw material gas pipe 44. Two source gases g2 (for example NH ₃ gas) can be introduced. Then, a second source gas g2 (for example, NH ₃ gas) is supplied from the first gas introduction unit 11 toward the substrate 90.

  That is, in the vapor phase growth apparatus 220, at least one of the first gas supply unit 10 and the second gas supply unit 20 (second gas supply unit 20 in this specific example) is a group III source gas. And the group V source gas are mixed, and the mixed group III source gas and group V source gas are supplied toward the reaction chamber 50 side of at least one of the gas supply units (second gas supply unit 20). A mixing unit (external mixing unit 45 in this specific example), and at least one of the gas supply units (second gas supply unit 20 in this specific example) includes a group III source gas mixed in the mixing unit and The group V source gas can be further supplied toward the substrate 90 disposed in the reaction chamber 50.

  In this specific example, the mixing section (external mixing section 45a) is provided in the second gas supply section 20, and the second gas supply section 20 is either the group III source gas or the group V source gas (this In this case, it further has a second pipe 22 into which Group V source gas) is introduced. The mixing unit (external mixing unit 45 a) is provided between the second pipe 22 and the reaction chamber 50. Then, a pipe (first raw material) into which one of the group III source gas and the group V source gas (in this case, the group III source gas) is introduced on the second pipe 22 side of the mixing part (external mixing part 45a). A gas pipe 13) is connected.

  In such a vapor phase growth apparatus 220, as step S <b> 110, the second source gas g <b> 2 is supplied from the second gas introduction unit 21 toward the substrate 90, and the first gas introduction unit 11 proceeds toward the substrate 90. A raw material gas g1 is supplied.

In step S 120, the mixed first source gas g 1 and second source gas g 2 are supplied from the second gas introduction unit 21 toward the substrate 90, and the first gas introduction unit 11 moves toward the substrate 90. Two source gases g2 are supplied.
Thus, according to the vapor phase growth apparatus 220, the vapor phase growth method illustrated in FIG. 10 can be realized.

FIG. 12 is a schematic view illustrating the configuration of another vapor phase growth apparatus according to the fourth embodiment of the invention.
As shown in FIG. 12, in the vapor phase growth apparatus 221 according to the present embodiment, the second gas introduction unit 21 of the first gas supply unit 10 in the vapor phase growth apparatus 220 illustrated in FIG. The piping 22 and the mixing piping 22a are connected, and the external mixing portion 45a is not provided. The other parts of the first gas supply unit 10, the third gas supply unit 30, the reaction chamber 50, and other configurations are the same as those of the vapor phase growth apparatus 220, and thus the description thereof is omitted.

  For example, at least one of hydrogen gas and nitrogen gas is introduced into the second pipe 22, and further, the second raw material gas is introduced into the second pipe 22 via the second valve 23v and the second mass flow controller 23m. A pipe 23 is connected. One of the group III source gas and the group V source gas (for example, a second source gas that is a group V source gas) is introduced into the second source gas pipe 23.

  The first raw material gas pipe 13 is connected to the mixing pipe 22a via the second distribution valve 15v, the first valve 13v, and the first gas mass flow controller 13m. One of a group III source gas and a group V source gas (for example, a first source gas that is a group III source gas) is introduced into the first source gas pipe 13.

In the vapor phase growth apparatus 221 having such a configuration, the following is performed in step S110. In the first gas supply unit 10, the supply of the second source gas g <b> 2 from the switching second source gas pipe 44 is stopped, and the first gas introduction unit 11 is supplied with the first source gas pipe 13 via the first source gas pipe 13. One source gas g 1 (for example, a group III source gas) is introduced, and the first source gas g 1 is supplied from the first gas introduction unit 11 toward the substrate 90.
In the second gas supply unit 20, the second distribution valve 15v is closed, and the second gas introduction unit 21 is connected to the second source gas g2 (for example, V2) via the second source gas pipe 23. Group source gas) is introduced, and the second source gas g2 is supplied from the second gas introduction part 21 toward the substrate 90.
Thus, the group III source gas and the group V source gas are supplied from different outlets toward the substrate 90 to grow the first semiconductor layer.

In step S120, the following is performed.
In the first gas supply unit 10, the first distribution valve 14v is closed, and the second source gas g2 (for example, V group source gas) is supplied from the switching second source gas pipe 44 to the first gas introduction unit 11. Is introduced, and the second source gas g2 is supplied from the first gas introduction part 11 toward the substrate 90.
In the second gas supply unit 20, the second distribution valve 15 v is opened, and the first source gas g 1 (eg, III) is supplied to the second gas introduction unit 21 via the first source gas pipe 13. The second source gas g2 (for example, group V source gas) is introduced via the second source gas pipe 23 at the same time as the group source gas) is introduced. And these gas is mixed in the upstream (direction opposite to the direction which goes to the board | substrate 90) rather than the edge part 11ae of the 1st partition plate 11a of the 2nd gas introduction part 21. FIG. Thus, the mixed first source gas g1 and second source gas g2 are supplied from the second gas introduction unit 21 toward the substrate 90. That is, the second gas introduction part 21 becomes an internal mixing part 21i for mixing the group III source gas and the group V source gas.

  In the vapor phase growth apparatus 221, the second gas supply unit 20 communicates with the reaction chamber 50 and supplies either one of a group III source gas and a group V source gas (for example, a first source gas that is a group III source gas). A third supply pipe (mixing pipe 22a) to be supplied into the reaction chamber 50 and the other one of the group III source gas and the group V source gas (for example, a second source material that is a group V source gas) communicated with the reaction chamber 50. And a fourth supply pipe (second pipe 22) for supplying the gas) into the reaction chamber 50. The mixing unit (internal mixing unit 21 i) is a portion inside the reaction chamber 50 where the third supply pipe and the fourth supply pipe are connected, and is on the substrate 90 side of the mixing unit (internal mixing unit 21 i). The group III source gas and the group V source gas are mixed with each other on the side of the third supply pipe and the fourth supply pipe from the end. The mixed group III source gas and group V source gas are supplied toward the substrate 90 from the same outlet (second gas introduction unit 21).

  The vapor phase growth apparatus 221 having such a configuration can also realize the vapor phase growth method illustrated in FIG.

(Fifth embodiment)
FIG. 13 is a schematic view illustrating a vapor phase growth method according to the fifth embodiment of the invention.
That is, FIG. 13A corresponds to a step (step S110) of growing a first semiconductor layer containing a nitride-based semiconductor having an Al composition ratio of 10 atomic percent or more, and FIG. 13B shows an Al composition ratio. Corresponds to a step (step S120) of growing a second semiconductor layer containing a nitride-based semiconductor of less than 10 atomic percent.

  As illustrated in FIG. 13A, the first source gas g <b> 1 is supplied from the first gas introduction unit 11 toward the substrate 90 during the growth of the first semiconductor layer. For example, trimethylaluminum (TMA) and TMG, which are group III source gases, are used as the first source gas g1, for example.

Then, the second source gas g <b> 2 is supplied from the second gas introduction unit 21 toward the substrate 90. As the second source gas, ammonia (NH ₃ ), which is a group V source gas, is used.

Then, the third source gas g3 is supplied from the third gas introduction unit 31 toward the substrate 90. For example, N ₂ is used as the third source gas. The third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

  Also in this case, the first source gas g1 and the second source gas g2 are separated from each other up to the end portion 11ae of the first partition plate 11a, and after exiting the first gas introduction portion 11 and the second gas introduction portion 21, respectively. However, the separated state is substantially maintained, and reaches the substrate 90 as a laminar flow gl. As a result, the reaction product hardly adheres to unnecessary portions other than the upper surface of the substrate 90, and the control range of the Al composition is wide in the first semiconductor layer to be grown, and a semiconductor layer having an arbitrary Al composition is easily obtained. Since the source gas reaches the substrate 90 in a laminar flow gl, the in-plane uniformity of the composition of the first semiconductor layer and the film thickness of the first semiconductor layer is high. The composition of the first semiconductor layer and the reproducibility of the film thickness of the first semiconductor layer are also good.

Then, as shown in FIG. 13B, during the growth of the second semiconductor layer, the first source gas g1 and the second source material are supplied from both the first gas inlet 11 and the second gas inlet 21. The gas g2 is mixed and supplied toward the substrate 90. For example, trimethylindium (TMI) and TMG, which are group III source gases, are used as the first source gas g1 at this time. Further, the group V source gas NH ₃ is used as the second source gas g2. That is, a mixed gas gm of a group III source gas TMI and a group V source gas NH ₃ is supplied from the first gas introduction unit 11 and the second gas introduction unit 21 toward the substrate 90.

Then, a third source gas g3 (for example, N ₂ ) is used from the third gas introduction part 31. Also in this case, the third source gas g3 flows toward the substrate 90 as a subflow for adjusting the gas flow.

Thus, since the mixed gas gm of TMI and NH ₃ can be supplied from both the first gas introduction part 11 and the second gas introduction part 21, it becomes easy to increase the ratio of the entire NH ₃ . That is, in both the first gas introduction part 11 and the second gas introduction 21, the generation of turbulent flow is suppressed by supplying the mixed gas gm of TMI and NH ₃ at a flow rate that does not generate turbulent flow. While maintaining the flow gl, the flow rate ratio of NH ₃ gas to the total flow rate can be increased. Accordingly, the second semiconductor layer having a low Al composition ratio is grown by increasing the flow rate ratio of the NH ₃ gas, the in-plane uniformity of the composition and film thickness in the second semiconductor layer is increased, and the composition in the second semiconductor layer and The reproducibility of the film thickness can be increased.

As described above, the vapor phase growth method according to the present embodiment also allows the group III source gas and the group V source gas to be directed toward the substrate 90 from different outlets (the first gas introduction unit 11 and the second gas introduction unit 21). The step of supplying and growing the first semiconductor layer (step S110), and the group III source gas and the group V source gas are mixed and supplied from the same outlet (for example, the first gas introduction unit 11) toward the substrate. And a step of growing the second semiconductor layer (step S120). In the present embodiment, the step S120 further mixes the group III source gas and the group V source gas from the outlet (second gas introduction part 21) different from the same outlet and proceeds toward the substrate 90. Supply.
Also by the vapor phase growth method according to the present embodiment, each of the semiconductor layers having different compositions can be formed with high in-plane uniformity and high reproducibility.

Such a vapor phase growth method can be carried out by using, for example, the following vapor phase growth apparatus.
FIG. 14 is a schematic view illustrating the configuration of a vapor phase growth apparatus according to the fifth embodiment of the invention.
As shown in FIG. 14, the vapor phase growth apparatus 230 according to the present embodiment includes both the external mixing unit 45 described with reference to FIG. 3 and the external mixing unit 45 a described with reference to FIG. 11.

That is, the mixing unit (the external mixing unit 45 and the external mixing unit 45a) is provided in both the first gas supply unit 10 and the second gas supply unit 20.
The first gas supply unit 10 further includes a first pipe 12 into which one of the group III source gas and the group V source gas is introduced, and the mixing unit (external mixing unit 45) is the first pipe 12. And the reaction chamber 50, and a pipe (mixing first) for introducing either the group III source gas or the group V source gas to the first pipe 12 side of the mixing section (external mixing section 45). Two source gas pipes 43) are connected.

  Furthermore, the second gas supply unit 20 further includes a second pipe 22 into which one of the group III source gas and the group V source gas is introduced, and the mixing unit (external mixing unit 45a) includes the second pipe 22. And the reaction chamber 50, and a pipe (first raw material) into which one of the group III source gas and the group V source gas is introduced on the second pipe 22 side of the mixing part (external mixing part 45a). A gas pipe 13) is connected.

  Thereby, step S110 and step S120 demonstrated regarding FIG. 13 can be implemented.

FIG. 15 is a schematic view illustrating the configuration of another vapor phase growth apparatus according to the fifth embodiment of the invention.
As shown in FIG. 15, in the vapor phase growth apparatus 231 according to this embodiment, the first gas supply unit 10 includes the first pipe 12 (first supply pipe) and the mixing pipe 42 described with reference to FIG. 9. (Second supply pipe) is provided, and the second gas supply unit 20 is further provided with the mixing pipe 22a (third supply pipe) and the second pipe 22 (fourth supply pipe) described with reference to FIG. Yes.

  The first gas supply unit 10 includes a first pipe 12 (first supply pipe) and a mixing pipe 42 (second supply pipe). The mixing unit (internal mixing unit 11 i) It is a part where the first supply pipe and the second supply pipe are connected to each other, and the first supply pipe and the second supply pipe are located at the end of the mixing unit (internal mixing unit 11i) on the substrate 90 side. On the side, the group III source gas and the group V source gas are mixed together.

  The second gas supply unit 20 includes a mixing pipe 22a (third supply pipe) and a second pipe 22 (fourth supply pipe), and the mixing unit (internal mixing unit 21i) is a reaction chamber. 50 is a portion where the third supply pipe and the fourth supply pipe are connected to each other, and the third supply pipe and the fourth supply from the end of the mixing unit (internal mixing unit 21i) on the substrate 90 side. On the tube side, the Group III source gas and the Group V source gas are mixed together.

  Thereby, step S110 and step S120 demonstrated regarding FIG. 13 can be implemented.

  In the vapor phase growth apparatuses 220, 221, 230, and 231 described above, the measurement unit 60 and the control unit 70 may be further provided.

  By the way, in the vapor phase growth method and vapor phase growth apparatus according to the embodiment of the present invention, when the horizontal reaction chamber 50 is used as in the vapor phase growth apparatuses 210 to 212, 220, 221, 230 and 231, III When supplying the group V source gas and the group V source gas from different outlets, the group V source gas is supplied from an outlet on the side close to the substrate 90 (lower side), and the side farther from the substrate 90 (upper side) than the outlet. It is desirable to supply the group III source gas from the outlet of As a result, the group III source gas and the V source gas are supplied in a layered form in the vicinity of the substrate 90 in a state where the group III source gas and the V source gas are appropriately separated, and a more uniform film formation can be performed.

(Sixth embodiment)
In the above, a horizontal reaction chamber is used, but in this embodiment, a vertical reaction chamber is used.
FIG. 16 is a schematic view illustrating the configuration of a vapor phase growth apparatus according to the sixth embodiment of the invention.
As shown in FIG. 16, the vapor phase growth apparatus 310 according to this embodiment includes a reaction chamber 50 that is a vertical reaction chamber. The first gas introduction unit 11 of the first gas supply unit 10, the second gas introduction unit 21 of the second gas supply unit 20, and the third gas introduction unit 31 of the third gas supply unit 30 include the reaction chamber 50. The susceptor 91 provided in the reaction chamber 50 is extended from the wall portion. The portions of the first gas supply unit 10, the second gas supply unit 20, and the third gas supply unit 30 outside the reaction chamber 50 have the same configuration as the vapor phase growth apparatus 210.

  In this specific example, a plurality of substrates 90 are placed on the susceptor 91. However, the present embodiment is not limited to this, and it may be designed such that one substrate 90 is placed on the susceptor 91.

  As shown in FIG. 16, the second gas introduction part 21, the first gas introduction part 11, and the third gas introduction part 31 are arranged in this order from the bottom to the top above the susceptor 91. .

  The second gas introduction part 21 includes a second horizontal extension part 421 extending in a horizontal direction (a direction parallel to the main surface of the susceptor 91) above the susceptor 91, and a downward direction from the second horizontal extension part 421. And a second vertical extending portion 421a extending. A plurality of second vertical extending portions 421a are provided. Thereby, the gas introduced into the reaction chamber 50 through the second pipe 22 passes through the second horizontal extending portion 421 and the second vertical extending portion 421a, and the substrate 90 placed on the susceptor 91. Introduced on top of.

  The first gas introduction part 11 includes a first horizontal extension part 411 extending in the horizontal direction above the susceptor 91, and a first vertical extension part 411 a extending downward from the first horizontal extension part 411. Have. A plurality of first vertical extending portions 411a are provided. As a result, the gas introduced into the reaction chamber 50 via the first pipe 12 passes through the first horizontal extension 411 and the first vertical extension 411a, and the substrate 90 placed on the susceptor 91. Introduced on top of.

  At this time, the 1st horizontal extension part 411 is isolate | separated by the 2nd horizontal extension part 421 and the partition. The first vertical extension 411a extends downward through the second horizontal extension 421. The first vertical extension 411a is separated from the second horizontal extension 421 by a partition wall. It is separated. The position of the first vertical extension 411a in the horizontal direction is different from the position of the second vertical extension 421a in the horizontal direction. With this configuration, the gas introduced through the first horizontal extension 411 and the first vertical extension 411a, the gas introduced through the second horizontal extension 421 and the second vertical extension 421a, Are supplied to the upper side of the substrate 90 through mutually different paths without being mixed with each other.

  The third gas introduction part 31 includes a third horizontal extension part 431 extending in the horizontal direction above the susceptor 91 and a third vertical extension part extending downward from the third horizontal extension part 431. 431a. A plurality of third vertical extending portions 431a are provided. As a result, the gas introduced into the reaction chamber 50 via the third pipe 32 passes through the third horizontal extending portion 431 and the third vertical extending portion 431a, and the substrate 90 placed on the susceptor 91. Introduced on top of.

  The third horizontal extension 431 is separated from the first horizontal extension 411 by a partition wall. The third vertical extension 431a extends downward through the first horizontal extension 411 and the second horizontal extension 421, but the third vertical extension 431a is the first horizontal extension 431a. The extending part 411 and the second horizontal extending part 421 are separated by a partition wall. The position of the third vertical extension 431a in the horizontal direction is different from the position of the first vertical extension 411a and the second vertical extension 421a in the horizontal direction. With this configuration, the gas introduced through the first horizontal extension 411 and the first vertical extension 411a, the gas introduced through the second horizontal extension 421 and the second vertical extension 421a, The gas introduced through the third horizontal extending portion 431 and the third vertical extending portion 431a is supplied above the substrate 90 without being mixed with each other through another path.

  Thus, also in this specific example, the first gas supply unit 10, the second gas supply unit 20, and the third gas supply unit 30 are separated from each other.

  Then, the already described first source gas g1, second source gas g2, and third source gas g3 are directed from the first gas supply unit 10, the second gas supply unit 20, and the third gas supply unit 30 toward the substrate 90. By supplying, the growth of the first semiconductor layer (step S110) and the growth of the second semiconductor layer (step S120) are performed. Also in this case, the group III source gas and the group V source gas are supplied from different outlets (for example, the first gas introduction unit 11 and the second gas introduction unit 21) toward the substrate 90, and the first semiconductor layer is formed. Grown up. Then, the group III source gas and the group V source gas are mixed and supplied from the same outlet (for example, the first gas introduction part 11) toward the substrate 90, and the second semiconductor layer is grown.

  In the step of growing the second semiconductor layer, a group III source gas and a group V source gas are supplied from an outlet (for example, the second gas inlet 21) different from the same outlet (for example, the first gas inlet 11). Any one of the above can be further supplied toward the substrate.

  As described with reference to FIG. 13, in the step of growing the second semiconductor layer, the group III is supplied from an outlet (second gas introduction part 21) different from the same outlet (for example, the first gas introduction part 11). The source gas and the group V source gas can be mixed and further supplied toward the substrate 90.

  That is, in the vapor phase growth apparatus 310 according to the present embodiment, the portion outside the reaction chamber 50 has the configuration of the portion outside the reaction chamber 50 in the vapor phase growth apparatuses 212, 220, 221, 230 and 231 already described. Applicable. Thereby, any of the operations described with reference to FIGS. 4, 10, and 13 can be performed.

  Further, in the vapor phase growth apparatus 310, and the vapor phase growth apparatus in which the configuration of the portion outside the reaction chamber 50 in the vapor phase growth apparatuses 212, 220, 221, 230, and 231 is applied in the vapor phase growth apparatus 310, the measurement unit 60 and a control unit 70 can be further provided.

  In the above description, the first source gas is a group III source gas and the second source gas is a group V source gas. However, the first source gas is a group V source gas, and the second source gas is a second source gas. May be a group III source gas. That is, a group III source gas and a group V source gas are supplied from different outlets toward the substrate 90, and a first semiconductor layer containing a nitride semiconductor having an Al composition ratio in group III of 10 atomic percent or more is grown. And a group III source gas and a group V source gas are mixed and supplied from the same outlet toward the substrate 90, and a second semiconductor containing a nitride-based semiconductor having an Al composition ratio of less than 10 atomic percent in the group III. It is sufficient if the semiconductor layer can be grown.

In this specification, “nitride-based semiconductor” refers to B _x In _y Al _z Ga _1-xyz N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x + y + z In the chemical formula ≦ 1), semiconductors having all compositions in which the composition ratios x, y, and z are changed within the respective ranges are included. Furthermore, in the above chemical formula, those that further include a group V element other than N (nitrogen), and those that further include any of various dopants added to control the conductivity type, etc. To be included.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, even if a person skilled in the art has made various changes regarding the shape, size, material, arrangement relationship, etc., of the specific configuration of each element constituting the vapor phase growth apparatus, the person skilled in the art will be within the scope of public knowledge. As long as the present invention can be implemented in the same manner by selecting as appropriate and the same effect can be obtained, it is included in the scope of the present invention.
Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, based on the vapor phase growth method and vapor phase growth apparatus described above as embodiments of the present invention, all vapor phase growth methods and vapor phase growth apparatuses that can be implemented by those skilled in the art with appropriate design changes are also included in the present invention. As long as the gist of the invention is included, it belongs to the scope of the present invention.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

  DESCRIPTION OF SYMBOLS 10 ... 1st gas supply part, 11 ... 1st gas introduction part, 11a ... 1st partition plate, 11ae ... End part, 11ah ... Through-hole, 11b ... 2nd partition plate, 11be ... End part, 11i ... Internal mixing part 12 ... 1st piping (1st supply pipe), 13 ... 1st raw material gas piping, 13m ... 1st mass flow controller, 13v ... 1st valve, 14v ... 1st valve for distribution, 15v ... 2nd valve for distribution, DESCRIPTION OF SYMBOLS 20 ... 2nd gas supply part, 21 ... 2nd gas introduction part, 21i ... Internal mixing part, 21n ... 2nd gas introduction wall, 22 ... 2nd piping (4th supply pipe), 22a ... Pipe for mixing (3rd Supply pipe), 23 ... second raw material gas pipe, 23m ... second mass flow controller, 23v ... second valve, 30 ... third gas supply section, 31 ... third gas introduction section, 31n ... third gas introduction wall, 32 ... Third distribution Pipe 33, third raw material gas pipe, 33 m, second mass flow controller, 33 v, third valve, 40, mixed gas supply section, 41, mixed gas introduction section, 41 c, first mixing section partition plate, 41 d, second Mixing part partition plate, 42 ... Mixing pipe (second supply pipe), 43 ... Mixing second source gas pipe, 43m ... Mixing gas mass flow controller, 43v ... Mixing gas valve, 44 ... Switching second source gas pipe 44m ... Switching gas mass flow controller, 44v ... Switching gas valve, 45, 45a ... External mixing unit, 50 ... Reaction chamber, 51 ... Gas introduction unit, 60 ... Measuring unit, 61 ... Optical monitor optical path, 62 ... Measurement data signal 70 ... Control unit 71 ... Mixed control signal line 72 ... First control signal line 73 ... Heater control signal line 80 ... Ga Supply unit, 90 ... substrate, 91 ... susceptor, 92 ... heater, 93 ... heater control unit, 101 ... buffer layer, 102 ... n-type contact layer, 103 ... light-emitting layer, 104 ... p-type electron block layer, 105 ... p-type Contact layer, 106 ... p-side transparent electrode, 107 ... p-side electrode, 108 ... n-side electrode, 110 ... semiconductor light emitting device, 210-212, 218, 219, 220, 221, 230, 231 and 310 vapor phase growth apparatus, 411 ... first horizontal extension part, 411a ... first vertical extension part, 421 ... second horizontal extension part, 421a ... second vertical extension part, 431 ... third horizontal extension part, 431a ... third vertical Extension part, bp ... reaction product, g1 ... first source gas, g2 ... second source gas, g3 ... third source gas, gl ... laminar flow, gm ... mixed gas, gt ... turbulent flow

Claims (11)

A vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas,
A reaction chamber in which the substrate is disposed;
Communicating with said reaction chamber, a first gas supply unit for supplying toward said group III material gas to the substrate,
Communicating with said reaction chamber, a second gas supply unit for supplying a pre-Symbol V group material gas toward the substrate,
With
The first gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the first gas supply unit. Having a first mixing section for feeding toward the side,
The first gas supply unit further includes a first pipe into which the group III source gas is introduced,
The first mixing unit is provided between the first pipe and the reaction chamber,
A pipe into which the group V source gas is introduced is connected to the first pipe side of the first mixing unit,
The first gas supply unit, a first operation and growing a first semiconductor layer of the group III material gas is supplied toward the substrate, the group III material gas is mixed in the first mixing section and The second group gas source gas is supplied toward the substrate and a second operation of growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer can be switched. There is a vapor phase growth apparatus. A vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas,
A reaction chamber in which the substrate is disposed;
Communicating with said reaction chamber, a first gas supply unit for supplying toward said group III material gas to the substrate,
Communicating with said reaction chamber, a second gas supply unit for supplying a pre-Symbol V group material gas toward the substrate,
With
The first gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the first gas supply unit. Having a first mixing section for feeding toward the side,
The first gas supply unit includes:
A first supply pipe communicating with the reaction chamber and supplying the group III source gas into the reaction chamber;
A second supply pipe communicating with the reaction chamber and supplying the group V source gas into the reaction chamber;
Have
The first mixing part is a part inside the reaction chamber to which the first supply pipe and the second supply pipe are connected,
The group III source gas and the group V source gas are mixed with each other on the first supply pipe and the second supply pipe side than the end of the first mixing part on the substrate side,
The first gas supply unit, a first operation and growing a first semiconductor layer of the group III material gas is supplied toward the substrate, the group III material gas is mixed in the first mixing section and The second group gas source gas is supplied toward the substrate and a second operation of growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer can be switched. There is a vapor phase growth apparatus. A vapor phase growth apparatus for vapor-phase-growing a nitride-based semiconductor layer on a substrate using a group III source gas and a group V source gas,
A reaction chamber in which the substrate is disposed;
Communicating with said reaction chamber, a first gas supply unit for supplying a pre-Symbol V group material gas toward the substrate,
Communicating with said reaction chamber, a second gas supply unit for supplying toward said group III material gas to the substrate,
With
Before Stories second gas supply unit, the group III material gas and by mixing the V group material gas, the mixed the group III material gas and the reaction chamber of the V group material gas and the second gas supply unit A first mixing section for feeding toward the side of
The second gas supply unit further includes a first pipe into which the group V source gas is introduced,
The first mixing unit is provided between the first pipe and the reaction chamber,
A pipe into which the group III source gas is introduced is connected to the first pipe side of the first mixing unit,
The second gas supply unit includes a first operation and growing a first semiconductor layer of the group V raw material gas is supplied toward the substrate, wherein the group III were mixed in the first mixing section the material gas and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. A vapor phase growth apparatus characterized by that. The second gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the second gas supply unit. A second mixing section for feeding toward the side,
  The second gas supply unit further includes a second pipe into which the group V source gas is introduced,
  The second mixing unit is provided between the second pipe and the reaction chamber,
  A pipe into which the group III source gas is introduced is connected to the second pipe side of the second mixing unit,
  The second gas supply unit supplies the group V source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the second mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. The vapor phase growth apparatus according to claim 1. The second gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the second gas supply unit. A second mixing section for feeding toward the side,
  The second gas supply unit further includes a third pipe into which the group V source gas is introduced,
  The second mixing unit is provided between the third pipe and the reaction chamber,
  A pipe into which the group III source gas is introduced is connected to the third pipe side of the second mixing unit,
  The second gas supply unit supplies the group V source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the second mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. The vapor phase growth apparatus according to claim 2. The second gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the second gas supply unit. A second mixing section for feeding toward the side,
  The second gas supply unit includes:
      A third supply pipe communicating with the reaction chamber and supplying the group III source gas into the reaction chamber;
      A fourth supply pipe communicating with the reaction chamber and supplying the group V source gas into the reaction chamber;
  Have
  The second mixing part is a part inside the reaction chamber to which the third supply pipe and the fourth supply pipe are connected,
  The group III source gas and the group V source gas are mixed with each other on the side of the third supply pipe and the fourth supply pipe from the end of the second mixing part on the substrate side,
  The second gas supply unit supplies the group V source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the second mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. The vapor phase growth apparatus according to claim 2. The first gas supply unit mixes the group III source gas and the group V source gas, and mixes the mixed group III source gas and the group V source gas in the reaction chamber of the first gas supply unit. A second mixing section for feeding toward the side,
  The first gas supply unit further includes a second pipe into which the group V source gas is introduced,
  The second mixing unit is provided between the second pipe and the reaction chamber,
  A pipe into which the group III source gas is introduced is connected to the second pipe side of the second mixing unit,
  The first gas supply unit supplies the group V source gas toward the substrate to grow a first semiconductor layer, the group III source gas mixed in the second mixing unit, and the It is possible to switch between a second operation of supplying a group V source gas toward the substrate and growing a second semiconductor layer having a group III composition ratio different from the group III composition ratio in the first semiconductor layer. The vapor phase growth apparatus according to claim 3. The group III source gas includes at least one selected from the group consisting of trimethylaluminum, triethylaluminum, dimethylaluminum hydride, ethyldimethylamine allane, triisobutylaluminum, trimethylindium, and triethylindium. The vapor phase growth apparatus according to any one of 1 to 7 . The at least one gas supply unit supplies either one of the group III source gas and the group V source gas toward the substrate, and includes a nitride semiconductor having a first Al composition ratio. The first operation for growing a layer, and the second Al which is lower than the first Al composition ratio by supplying the group III source gas and the group V source gas mixed in the mixing section toward the substrate. The vapor phase growth according to any one of claims 1 to 8, wherein the second operation of growing a second semiconductor layer containing a nitride-based semiconductor having a composition ratio can be performed by switching. apparatus. The Al composition ratio in the first semiconductor layer is 10 atomic percent or more,
The vapor phase growth apparatus according to claim 9, wherein the Al composition ratio in the second semiconductor layer is less than 10 atomic percent. A measuring unit for measuring optical characteristics of the surface of the substrate during the growth of the second semiconductor layer;
Based on at least one of the temperature of the substrate derived from the optical characteristics measured by the measurement unit, the growth rate of the second semiconductor layer, and the composition of the second semiconductor layer, A control unit for controlling a mixing ratio with the group V source gas;
The vapor phase growth apparatus according to any one of claims 1 to 10 , further comprising:

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