JP2005228757A - Apparatus and method for growing vapor phase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase growing apparatus which performs like the manufacture of a gallium nitride compound semiconductor, which heats a substrate to a high temperature of 1000°C or higher, and which can vapor phase grow efficiently a semiconductor film uniformly with proper crystallinity on a plurality of substrates, and to provide a vapor phase growing method. <P>SOLUTION: The vapor phase growing apparatus includes an annular susceptor 3 which lays the substrate 2 horizontally in a reaction chamber 1, a heater 4 which heats the substrate 2, a supply tube 5 which introduces a first material gas from the core of the annular susceptor 3 in the reaction chamber 1, a supply tube 6 which introduces a second material gas to the reaction chamber 1 from the core of the wall surface of the reaction chamber 1 facing the annular susceptor 3, and a reactant gas discharging unit 7. Moreover, the substrate 2 is heated by the heater 4 by using the vapor phase growing apparatus, and the first material gas and the second material gas are introduced into the reaction chamber 1 to subject the semiconductor film to vapor phase growth on the substrate 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor film vapor phase growth apparatus, and more particularly, to a semiconductor film vapor phase growth comprising a susceptor for placing a substrate, a heater for heating the substrate, a source gas introduction unit, and a reaction gas discharge unit. The present invention relates to an apparatus and a vapor phase growth method.

  In recent years, the demand for gallium nitride-based compound semiconductors has been increasing rapidly as an element such as a light-emitting diode or a laser diode, mainly in the lighting field. As a method for producing a gallium nitride compound semiconductor, for example, an organic metal gas such as trimethylgallium, trimethylindium, or trimethylaluminum is used as a group III metal source, ammonia is used as a nitrogen source, and sapphire is set in advance in a reaction chamber. A method of forming a semiconductor film of a gallium nitride compound on a substrate by vapor growth is known.

  The apparatus for producing the gallium nitride compound semiconductor includes a susceptor for placing the substrate in a horizontal direction, a heater for heating the substrate, a source gas introduction unit, a reaction gas discharge unit, and a susceptor rotation for supporting the susceptor. There are horizontal or vertical vapor phase growth apparatuses with shafts. In such a vapor phase growth apparatus, a substrate is placed on a susceptor and heated by a heater, and then two kinds of gases containing the above-mentioned raw materials are supplied to the surface of the substrate from the horizontal direction, or in the horizontal direction and above. By supplying from the direction, a semiconductor film is formed on the substrate by vapor deposition.

In the manufacture of gallium nitride compound semiconductors, since the substrate is heated to a high temperature of 1000 ° C. or higher, the source gas diffuses due to the thermal convection in the vicinity of the substrate and does not reach the substrate efficiently, and is uniform and has good crystallinity. There is a problem that a semiconductor film cannot be obtained or the growth rate is slow. For this reason, a pressure gas introduction part is provided on the reaction chamber wall facing the substrate, and a pressure gas that does not affect the reaction such as carrier gas is supplied into the reaction chamber in a direction perpendicular to the substrate, and the flow of the source gas is changed to the substrate. A vapor phase growth apparatus and a vapor phase growth method have been developed which are changed in the direction of spraying. According to this, it is said that a semiconductor film with good crystallinity can be obtained by appropriately controlling the flow rate of the pressing gas in accordance with the type and flow rate of the source gas, the heating temperature of the substrate, and the like.
Japanese Patent Laid-Open No. 11-121386 JP 2001-250783 A

  However, in the vapor phase growth apparatus and the vapor phase growth method, at least one gas out of the gas containing the raw material is supplied to the surface of the substrate from the horizontal direction. When performing growth, although the susceptor is rotated, the substrate on the most upstream side of the gas flow and the substrate on the most downstream side are considerably separated from each other, and the situation of the vapor phase growth reaction at each position, for example, the raw material in the gas Since the concentrations and the like differ greatly, there is a possibility that the quality of the semiconductor film is adversely affected.

  Therefore, the problem to be solved by the present invention is a semiconductor having a uniform and good crystallinity on a substrate even when simultaneous vapor phase growth of a plurality of substrates is performed in the manufacture of a gallium nitride compound semiconductor or the like. To provide a vapor phase growth apparatus and a vapor phase growth method capable of efficiently vapor-depositing a film.

  As a result of intensive studies to solve these problems, the present inventors have used an annular susceptor as a susceptor for mounting a plurality of substrates in the horizontal direction, and introduced the first source gas into the reaction chamber from the center thereof. In addition, by adopting a configuration in which the second source gas is introduced into the reaction chamber from the center of the reaction chamber wall surface facing the annular susceptor, vapor phase growth is performed on the substrate at any position under substantially the same conditions. In addition, it has become possible to alleviate the diffusion of the source gas due to thermal convection, and it has been found that a semiconductor film having uniform and good crystallinity can be obtained efficiently, and has reached the vapor phase growth apparatus and vapor phase growth method of the present invention. .

  That is, the present invention relates to an annular susceptor for horizontally placing a substrate in a reaction chamber, a heater for heating the substrate, a supply pipe for introducing a first source gas into the reaction chamber from the center of the annular susceptor, and the annular susceptor. And a supply pipe for introducing the second source gas into the reaction chamber from the central portion of the reaction chamber wall surface facing to the reaction chamber, and a reaction gas discharge section.

  In the present invention, the substrate is placed on the annular susceptor in the reaction chamber, the substrate is heated with a heater, and the first source gas is introduced into the reaction chamber from the center of the annular susceptor, and is opposed to the annular susceptor. It is also a vapor phase growth method characterized in that a second source gas is introduced into the reaction chamber from the center of the reaction chamber wall surface and a semiconductor film is vapor grown on the substrate.

The present invention is applied to a vapor phase growth apparatus and a vapor phase growth method including a susceptor for placing a substrate, a heater for heating the substrate, a source gas introduction pipe, and a reaction gas discharge unit.
In the vapor phase growth apparatus of the present invention, the type of the raw material gas is not particularly limited. However, particularly in the case of manufacturing a gallium nitride compound semiconductor that requires a high temperature of 1000 ° C. or higher as the vapor phase growth temperature, it is possible to efficiently vapor phase grow a uniform semiconductor film with good crystallinity on the substrate. The effects of the present invention can be sufficiently exhibited.

Hereinafter, although the vapor phase growth apparatus and vapor phase growth method of this invention are demonstrated in detail based on FIGS. 1-4, this invention is not limited by these.
1 to 4 are vertical sectional views showing an example of a vapor phase growth apparatus of the present invention. As shown in FIG. 1, the vapor phase growth apparatus of the present invention includes an annular susceptor 3 for placing a substrate 2 in a reaction chamber 1 in a horizontal direction, a heater 4 for heating the substrate, and a first portion from the center of the annular susceptor. A supply pipe 5 for introducing the source gas into the reaction chamber, a supply pipe 6 for introducing the second source gas into the reaction chamber from the center of the reaction chamber wall facing the annular susceptor, and a reaction gas discharge section 7 are provided. It is a vapor phase growth apparatus. Preferably, a susceptor rotation shaft 8 is set.

  The vapor phase growth apparatus shown in FIG. 1 introduces a first source gas into the reaction chamber from below the central portion of the annular susceptor, and introduces the second source gas into the central portion of the reaction chamber wall facing the annular susceptor. As shown in FIG. 2, an annular susceptor is set on the upper side of the reaction chamber, and the first source gas is introduced into the reaction chamber from the upper side to the lower side. It is also possible to adopt a structure in which the second source gas is introduced into the reaction chamber from the bottom upward. Also in the vapor phase growth apparatus shown in FIGS. 3 and 4, the introduction direction of the source gas can be changed as described above.

  In the vapor phase growth apparatus of the present invention, an annular susceptor is used as a susceptor on which a substrate is placed. This susceptor is usually set so that substrates that can rotate can be placed at equal intervals. Further, the opposite surface of the annular susceptor is provided with a wall surface that is approximately the same size as the annular susceptor, and the second source gas introduction pipe faces the first source gas introduction pipe through the reaction chamber. Set to position. Normally, between the first source gas inlet and the second source gas inlet, the first source gas and the second source gas are in front of each other as shown in FIGS. The guide member 9 is used so that the turbulent flow is prevented from mixing and the second source gas is directed toward the substrate surface.

  In the vapor phase growth apparatus of the present invention, it is preferable that the second source gas supply pipe is set so that its inner diameter increases toward the reaction chamber, as shown in FIGS. Furthermore, it is preferable to set a guide member 10 at the reaction chamber inlet of the second source gas supply pipe so that the second source gas faces the substrate as shown in FIG. By adopting such a configuration, when the substrate needs to be heated to a high temperature of 1000 ° C. or more as in the case of manufacturing a gallium nitride compound semiconductor, for example, diffusion of the source gas due to thermal convection can be reduced. .

  The vertical gap in the reaction chamber (the gap between the annular susceptor and the reaction chamber wall facing this) is usually set to 3 to 30 mm, preferably about 5 to 20 mm. If the vertical gap in the reaction chamber is less than 3 mm, the flow of the raw material gas becomes too fast, which may reduce the reaction efficiency and slow the growth rate. In addition, when it exceeds 30 mm, even if the guide member is set as described above, the second source gas is difficult to reach the substrate, and the growth rate may be slow.

The vapor phase growth method of the present invention is a method in which a semiconductor film is vapor-phase grown on a substrate using the above-described vapor phase growth apparatus. That is, the substrate is placed on the annular susceptor in the reaction chamber, the substrate is heated with a heater, the first source gas is introduced into the reaction chamber from the central portion of the annular susceptor, and from the central portion of the reaction chamber wall facing the annular susceptor. This is a method in which a second source gas is introduced into a reaction chamber and a semiconductor film is vapor-grown on a substrate.
The vapor phase growth method of the present invention is particularly suitable for the production of gallium nitride compound semiconductors, but is not limited thereto.

  When a gallium nitride compound semiconductor is produced by the vapor phase growth method of the present invention, a gas containing ammonia, monomethylhydrazine, dimethylhydrazine, tert-butylhydrazine, or trimethylamine is usually used as the first source gas. As the second source gas, a gas containing trimethylgallium, triethylgallium, trimethylindium, triethylindium, trimethylaluminum, or triethylaluminum is used. The second source gas may further contain bisethylcyclopentadienyl magnesium, silane, or organosilane.

In addition, the vapor phase growth method of the present invention can be widely applied from a relatively low temperature vapor phase growth where the maximum heating temperature of the substrate is about 600 ° C. to a relatively high temperature vapor phase growth of 1000 ° C. or more. Further, the pressure in the reaction chamber may be a normal pressure or a reduced pressure of 1 kPa (abs) to a pressurized pressure of 1 MPa (abs).
When performing vapor phase growth according to the present invention, it is preferable to rotate and revolve the substrate in order to efficiently vapor phase grow a uniform semiconductor film on the substrate.

  The vapor phase growth apparatus and the vapor phase growth method of the present invention introduce a first source gas into the reaction chamber from the central portion of the annular susceptor, and the second source gas from the central portion of the reaction chamber wall surface facing this. Is introduced into the reaction chamber, a plurality of substrates at any position are subjected to vapor phase growth under substantially the same conditions. In addition, since the second source gas can be set to be introduced from an oblique direction with respect to the substrate surface, it is possible to reduce the diffusion of the source gas due to thermal convection. Therefore, even when it is necessary to heat the substrate to a high temperature of 1000 ° C. or higher as in the case of manufacturing a gallium nitride compound semiconductor, a semiconductor film having uniform and good crystallinity is efficiently vapor-grown on a plurality of substrates It is possible.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these.

(Production of vapor phase growth equipment)
Inside a quartz reaction vessel (inner dimensions, inner diameter 300 mm, height 100 mm), facing the annular susceptor (diameter 260 mm, thickness 5 mm, central opening diameter 10 mm), heater, and annular susceptor A wall surface (diameter 260 mm, thickness 10 mm) is provided, and further, a first source gas supply pipe at the center of the annular susceptor, a second source gas supply pipe at the center of the wall surface, a guide member, and a reaction gas discharge unit The vapor phase growth apparatus as shown in FIG. 3 was manufactured. The inner diameter of the first source gas supply pipe was 10 mm, the inner diameter of the second source gas supply pipe other than the supply port was 10 mm, and the inner diameter of the supply port was 30 mm. The vertical gap in the reaction chamber was 15 mm.

(Vapor phase growth experiment)
Using this apparatus, a GaN crystal was grown on a sapphire substrate having a diameter of 2 inches as follows.
After five sapphire substrates were set on the susceptor at equal intervals and the reaction chamber was replaced with hydrogen gas, hydrogen was supplied from the first source gas supply pipe at 15 L / min, and hydrogen was supplied from the second source gas supply pipe. The substrate was heated to 1150 ° C. while supplying 15 L / min, and the substrate was heat-treated for 10 minutes.

  Next, the temperature of the substrate was lowered to 500 ° C. and allowed to stand until stable. Subsequently, the susceptor is rotated 12 times per minute, the substrate is rotated 36 times per minute, and a mixed gas of ammonia and hydrogen (ammonia 20 L / min, hydrogen 10 L / min) is supplied from the first source gas supply pipe, Hydrogen gas containing trimethylgallium (trimethylgallium 120 μmol / min, hydrogen 25 L / min) was supplied from the second source gas supply pipe, and low-temperature vapor phase growth of GaN was performed for 2 minutes.

  After the low temperature growth layer was formed, the supply of trimethylgallium was stopped, only a mixed gas of ammonia and hydrogen was supplied, and the temperature of the substrate was raised to 1100 ° C. and allowed to stand until stable. Next, a mixed gas of ammonia and hydrogen (ammonia 40 L / min, hydrogen 10 L / min) is supplied from the first source gas supply pipe, and hydrogen gas containing trimethylgallium is again supplied from the second source gas supply pipe ( (Trimethylgallium 240 μmol / min, hydrogen 50 L / min) was supplied, and vapor phase growth of GaN was performed for 60 minutes. Thus, the vapor phase growth was repeated 5 times.

(Evaluation of GaN film)
After completion of the vapor phase growth, the substrate was taken out and the film thickness distribution of GaN was measured to evaluate the uniformity. Since the substrate rotates during the vapor phase growth, the film thickness distribution was measured from the center to the end of the substrate. Table 1 shows the results of measuring the film thickness and the fluctuation range ((maximum value−minimum value) / average value). Furthermore, in order to evaluate the crystal quality and electrical characteristics of the grown film, Table 1 shows the results of X-ray diffraction (half width of (002) plane) and hole measurement (mobility) for five substrates. Shown in In addition, a numerical value is an average value and Example 2 is the same as this.

The production of the vapor phase growth apparatus of Example 1 was carried out except that a conical guide member was set at the inlet of the second source gas supply pipe so that the second source gas was directed toward the substrate surface. In the same manner as in Example 1, a vapor phase growth apparatus as shown in FIG.
A vapor phase growth experiment and evaluation of the GaN film were performed in the same manner as in Example 1 except that this vapor phase growth apparatus was used. The results are shown in Table 1.

(Comparative Example 1)
In the production of the vapor phase growth apparatus of Example 1, the vapor phase growth apparatus was produced in the same manner as in Example 1 except that the first source gas supply pipe was not provided.
Using this apparatus, a GaN crystal was grown on a sapphire substrate having a diameter of 2 inches as follows.
After five sapphire substrates were set on the susceptor at equal intervals and the reaction chamber was replaced with hydrogen gas, the substrate was heated to 1150 ° C. while supplying hydrogen at 30 L / min from the second source gas supply pipe. The heat treatment was performed for 10 minutes.

  Next, the temperature of the substrate was lowered to 500 ° C. and allowed to stand until stable. Subsequently, the susceptor is rotated 12 times per minute, the substrate is rotated 36 times per minute, and a mixed gas of ammonia and hydrogen containing trimethylgallium (trimethylgallium 120 μmol / min, ammonia 20 L / min, Hydrogen 35 L / min) was supplied, and low-temperature vapor phase growth of GaN was performed for 2 minutes.

  After forming the low-temperature growth layer, only a mixed gas of ammonia and hydrogen was supplied, and the temperature of the substrate was raised to 1100 ° C. and left until it was stabilized. Next, a mixed gas of trimethylgallium-containing ammonia and hydrogen (trimethylgallium 240 μmol / min, ammonia 40 L / min, hydrogen 60 L / min) is supplied again from the second source gas supply pipe, and vapor phase growth of GaN is performed for 60 times. For a minute. Thus, the vapor phase growth was repeated 5 times. Table 1 shows the results of the vapor phase growth experiment and the GaN film evaluation performed in the same manner as in Example 1 after the completion of the vapor phase growth.

Vertical sectional view showing an example of the vapor phase growth apparatus of the present invention Vertical sectional view showing an example of a vapor phase growth apparatus other than FIG. 1 of the present invention Vertical sectional view showing an example of a vapor phase growth apparatus other than FIGS. 1 and 2 of the present invention Vertical sectional view showing an example of a vapor phase growth apparatus other than FIGS. 1 to 3 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Substrate 3 Annular susceptor 4 Heater 5 First source gas supply pipe 6 Second source gas supply pipe 7 Reaction gas discharge part 8 Susceptor rotating shaft 9 Guide member 10 Guide member

Claims (11)

  An annular susceptor for horizontally placing the substrate in the reaction chamber, a heater for heating the substrate, a supply pipe for introducing the first source gas into the reaction chamber from the center of the annular susceptor, and a reaction chamber facing the annular susceptor A vapor phase growth apparatus comprising: a supply pipe for introducing a second source gas into a reaction chamber from a central part of a wall surface; and a reaction gas discharge part.   The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus is an apparatus for producing a gallium nitride compound semiconductor.   The vapor phase growth apparatus according to claim 1, wherein the susceptor is configured to mount a plurality of substrates.   The vapor phase growth apparatus according to claim 1, wherein a guide member is set at a mixing position of the first source gas and the second source gas so that the second source gas faces the substrate.   The vapor phase growth apparatus according to claim 1, wherein an inner diameter of the second source gas supply pipe is set so as to increase toward the reaction chamber.   2. The vapor phase growth apparatus according to claim 1, wherein a guide member is set at a reaction chamber supply port of the second source gas supply pipe so that the second source gas is directed toward the substrate.   The vapor phase growth apparatus according to claim 1, wherein a vertical gap of the reaction chamber is 3 to 30 mm.   The substrate is placed on the annular susceptor in the reaction chamber, the substrate is heated with a heater, the first source gas is introduced into the reaction chamber from the central portion of the annular susceptor, and the central portion of the reaction chamber wall facing the annular susceptor A second source gas is introduced into the reaction chamber, and a semiconductor film is vapor-phase grown on the substrate.   The first source gas is a gas containing ammonia, monomethylhydrazine, dimethylhydrazine, tert-butylhydrazine, or trimethylamine, and the second source gas is trimethylgallium, triethylgallium, trimethylindium, triethylindium, trimethylaluminum, The vapor phase growth method according to claim 8, wherein the gas is a gas containing triethylaluminum.   The vapor phase growth method according to claim 9, wherein the second source gas is a gas further containing bisethylcyclopentadienylmagnesium, silane, or organosilane. The vapor phase growth method according to claim 8, wherein the second source gas is introduced toward the substrate surface.

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