JP2005093505A - Vapor phase epitaxial growth device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lateral vapor phase epitaxial growth device which has a relative structure of a susceptor and a temperature soaking plate that is capable of heating a substrate uniformly so as to make crystals more uniform in characteristics through its surface. <P>SOLUTION: The lateral vapor phase epitaxial growth device is equipped with the temperature soaking plate 4 which is stacked up on the substrate 2 housed and supported inside the opening 7 of the susceptor 1, and overlapped with the rear surface of the substrate 2, the substrate 2, and a heating means 8 for heating both the temperature soaking plate 4 and the susceptor 1. The temperature soaking plate 4 which is so shaped as to cover the substrate 2 is installed on the substrate 2. The temperature soaking plate 4 is formed with the lower contacting surface 4a of the same shape with that of the substrate 2, and an upper temperature soaking plate 4b that is so shaped as to cover the substrate 2, and may be installed on the substrate 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a horizontal vapor phase epitaxial growth apparatus for supplying a source gas in a radial direction from the diameter direction or center of a susceptor on a heated substrate, thermally decomposing the source gas, and growing a compound semiconductor crystal on the substrate in a vapor phase, In particular, the present invention relates to the relative structure of a temperature-uniforming plate and a susceptor set adjacent to the substrate in order to heat the substrate uniformly.

  Since FETs and HEMTs using compound semiconductor crystals have higher electron mobility than silicon semiconductors, they are widely used in high-frequency equipment amplifiers that require high-speed operation and high efficiency in recent years, such as mobile phones and satellite broadcast receivers. The demand is expected to grow further.

  At present, in the so-called semiconductor element as described above, as one of the methods for growing the compound semiconductor crystal, there are many MOVPE (organometallic vapor phase epitaxy) methods for performing epitaxial growth using an organic metal as a main raw material. . In the MOVPE method, a group III organometallic source gas and a group V source gas are introduced into a reaction furnace as a mixed gas with a high-purity hydrogen carrier gas, and the source material is pyrolyzed near the substrate heated in the reaction furnace. A compound semiconductor crystal grows epitaxially on the substrate.

  Here, FIG. 6 shows a system for constructing a reactor (reactor) employed by a conventional main MOVPE apparatus. 6A shows a barrel type in which a semiconductor substrate (wafer) 2 is held on a pyramidal slope of the susceptor 11, FIG. 6B shows a gas flowing in one direction from one side of the reaction tube 10 to the other side, and FIG. 6C shows a gas in which the substrate 2 is provided face-down in the opening of the susceptor 1 (horizontal face-down). FIG. 6C shows a gas flowing from the top to the bottom in the radial direction from the center of the susceptor 12. In FIG. 6 (d), a gas directed upward from the bottom flows upward in the radial direction from the center of the susceptor 1, and the substrate 2 of the susceptor 1 is provided. The type (rotation and revolution type face-down) provided face-down in the opening is shown. Among these, FIGS. 6B to 6D belong to a horizontal vapor phase epitaxial growth apparatus.

  FIG. 5 shows a schematic diagram of a conventional horizontal vapor phase epitaxial growth apparatus. As shown in FIG. 5, a conventional horizontal vapor phase epitaxial growth apparatus 9 is provided facing a reaction tube 10 including a gas rectifier tube having a gas introduction port 10a and a gas exhaust port 10b at both ends, and the reaction tube 10 inside. Along with the susceptor 1 having a plurality of openings 7 in the circumferential direction for accommodating and supporting the substrate 2 with the front side of the substrate 2 facing down, and on the back side of the substrate 2 accommodated and supported in the opening of the susceptor 1 A temperature soaking plate 4 provided adjacent thereto, and a heater (heating means) 8 provided above the susceptor 1 for thermally decomposing the source gas G by heating the substrate, the temperature soaking plate and the susceptor, and A motor (rotating means) 6 for rotatably supporting the susceptor 1 is provided (for example, see Patent Document 1).

  In the case of the horizontal face-down method of FIG. 6B or the rotation / revolution type face-down type compound semiconductor manufacturing apparatus of FIG. 6D, the semiconductor substrate 2 is mounted in the opening 7 of the susceptor 1 as shown in FIG. In order to obtain a structure to be placed and supported, a substrate support portion consisting of a step projecting in the center direction of the opening 7, specifically, an inward claw 3, is integrally formed on the peripheral surface of the lower surface of the opening 7. The outer periphery is supported by the inward nails 3 and held on the lower surface of the opening 7.

  That is, as shown in FIG. 4, a wafer-shaped hole for epitaxial growth is cut through the susceptor 1. A semiconductor wafer (substrate 2) is supported by the inward claws 3 in the penetrating portion, and a temperature-equalizing plate 4 is placed thereon to perform epitaxial growth.

  The temperature soaking plate 4 is installed in order to improve the in-plane uniformity of epitaxial growth. However, even if the temperature soaking plate 4 is used, there is a problem that the wafer periphery is inferior in in-plane uniformity. This is because the temperature of the peripheral part of the temperature-uniforming plate 4 is not uniform. For this reason, the uniformity of the peripheral portion of the wafer (substrate 2) having the same shape as the temperature soaking plate 4 was also poor. Further, even in a slight gap between the wafer (substrate 2), the temperature soaking plate 4 and the susceptor 1, gas is turbulent during epitaxial growth, and the uniformity of the peripheral portion of the wafer (substrate 2) is deteriorated.

On the other hand, in the conventional apparatus for manufacturing an oxide glass thin film for forming an optical waveguide or the like, in order to keep the substrate temperature uniform during the deposition of glass particles, a temperature uniformity obtained by processing a material such as SiC into a disk shape. It is known to support on a turntable via a hot plate (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 11-87252 JP-A-6-135728

  However, Patent Document 2 merely shows a configuration in which a substrate is placed on a temperature-uniform heat plate having a larger area in an oxide glass thin film manufacturing apparatus, and the opening of a susceptor that is the subject of the present invention. There is no mention of the structure of the temperature soaking plate provided on the back side (the side opposite to the material gas flow path) of the substrate housed therein. Such a difference comes from the essence of both, and in Patent Document 2, there is no problem even if a step is caused by placing a substrate on a temperature-uniform plate, whereas the present invention is a horizontal vapor phase epitaxial growth apparatus. Therefore, it can be contrasted that the existence of such a step disturbs the flow of the material gas and becomes a major obstacle to vapor phase epitaxial growth.

  In the conventional horizontal vapor phase epitaxial growth apparatus, little attention has been paid to the structure of the temperature soaking plate set adjacent to the substrate in order to heat the substrate uniformly. That is, as shown in FIG. 4, a temperature equalizing plate having the same shape as the substrate as viewed in the vertical direction is simply stacked on the substrate and accommodated in the opening.

  For this reason, there is a problem that even if a temperature soaking plate is used, in-plane uniformity is inferior at the wafer peripheral portion. This is because the temperature in the peripheral portion of the temperature-uniforming plate is not uniform. For this reason, the uniformity of the peripheral portion of the wafer having the same shape as the temperature soaking plate was also poor. Further, even in a slight gap between the wafer, the temperature soaking plate, and the susceptor, the gas turbulent during epitaxial growth, which deteriorates the uniformity of the peripheral portion of the wafer.

  Therefore, the conventional horizontal vapor phase epitaxial growth apparatus has a problem in that the uniformity of crystal characteristics (growth rate, mixed crystal ratio, carrier concentration) in the wafer surface, especially the peripheral portion, is poor in the MOVPE epitaxial growth. was there. When the in-plane uniformity deteriorates, the characteristics of the semiconductor element using the same also vary, resulting in a decrease in manufacturing yield.

  Therefore, an object of the present invention is to solve the above-mentioned problems and to have a relative structure of a temperature-uniforming plate and a susceptor that can heat the substrate uniformly so as to reduce the variation in crystal characteristics in the substrate plane. It is an object to provide a horizontal vapor phase epitaxial growth apparatus.

  In order to achieve the above object, the present invention is configured as follows.

  A vapor phase epitaxial growth apparatus according to a first aspect of the present invention is provided so as to face the inside of a reaction tube, and has a susceptor having an opening for storing and supporting the substrate with the front side of the substrate facing the reaction tube, and the susceptor In a horizontal vapor phase epitaxial growth apparatus comprising: a temperature soaking plate provided on the back side of a substrate housed and supported in the opening of the substrate; and a heating means for heating the substrate, the temperature soaking plate and the susceptor. As the temperature soaking plate, a temperature soaking plate having a shape covering the substrate is provided on the substrate.

  The vapor phase epitaxial growth apparatus according to the first aspect of the present invention includes both the embodiments shown in FIGS.

  In the present invention (Claims 1 to 6), the horizontal vapor phase epitaxial growth apparatus roughly includes two forms. First, a plurality of substrates are disposed on a rotating plate-shaped susceptor in a circumferential direction at a position slightly away from the center of the susceptor, and a lower surface serving as a growth surface is supported toward the gas flow path side. FIG. 6B shows a compound semiconductor manufacturing apparatus (FIG. 6B) in which a susceptor is heated with a heater from the back surface side, a source gas is flowed in the diameter direction of the susceptor, and a semiconductor crystal is epitaxially grown on the heated substrate. Second, a plurality of substrates are disposed on a rotating plate-shaped susceptor in a circumferential direction at a position slightly away from the center of the susceptor, and a lower surface serving as a growth surface is supported toward the gas flow path side. 6 is a compound semiconductor manufacturing apparatus (FIGS. 6C and 6D) in which a susceptor is heated with a heater from the back surface side, a source gas is flowed radially from the central portion of the susceptor, and semiconductor crystals are epitaxially grown on the heated substrate.

  More specifically, the face-down type (FIGS. 6A and 6D) in which the lower surface of the substrate faces the gas flow path and the temperature equalizing plate is located on the upper surface side of the substrate, and the upper surface of the substrate is the gas flow path. There is a face-up type (FIG. 6C) in which the temperature soaking plate is located on the lower surface side of the substrate. Any of these forms is included in the concept of the horizontal vapor phase epitaxial growth apparatus of the present invention.

  According to a second aspect of the present invention, in the vapor phase epitaxial growth apparatus according to the first aspect, a temperature soaking plate having an area of 1.25 to 2 times the substrate area is provided on the substrate.

  Here, the area of the temperature soaking plate is set to 1.25 to 2 times the substrate area. If it is less than 1.25 times, the heat soaking effect on the substrate is poor, and if it is more than 2 times, the temperature soaking plate is unnecessarily high. This is because the area becomes large and uneconomical.

  According to a third aspect of the present invention, in the vapor phase epitaxial growth apparatus according to the first aspect, a temperature soaking plate having a length 1.1 to 1.4 times the diagonal or diameter of the substrate is provided on the substrate. Features.

  Here, the size of the temperature soaking plate is 1.1 to 1.4 times the diagonal or diameter of the substrate. If it is less than 1.1 times, the soaking effect on the substrate is poor. If it is four times or more, the area of the temperature soaking plate becomes unnecessarily large, which is uneconomical.

  According to a fourth aspect of the present invention, there is provided a vapor phase epitaxial growth apparatus that faces the inside of a reaction tube, and has a susceptor having an opening for storing and supporting the substrate with the front side of the substrate facing the reaction tube, and the susceptor In a horizontal vapor phase epitaxial growth apparatus comprising: a temperature soaking plate provided on the back side of a substrate housed and supported in the opening of the substrate; and a heating means for heating the substrate, the temperature soaking plate and the susceptor. As the temperature soaking plate, a temperature soaking plate having a contact surface portion having the same shape as that of the substrate and a soaking plate portion shaped so as to cover the substrate is provided on the substrate.

  The vapor phase epitaxial growth apparatus according to the fourth aspect of the invention specifies the embodiment shown in FIG.

  According to a fifth aspect of the present invention, there is provided the vapor phase epitaxial growth apparatus according to the fourth aspect, wherein a temperature soaking plate having a contact surface portion having the same shape as the substrate and having an area of 1.25 to 2 times the substrate area is formed on the substrate. It is characterized by having been installed in. The significance of setting the area of the temperature soaking plate to 1.25 to 2 times the substrate area is the same as that of the second aspect.

  According to a sixth aspect of the present invention, in the vapor phase epitaxial growth apparatus according to the fourth aspect, the contact surface portion has the same shape as the substrate and has a length 1.1 to 1.4 times the diagonal or diameter of the substrate. It is characterized in that a temperature soaking plate is installed on the substrate. The significance of setting the size of the temperature soaking plate to be 1.1 to 1.4 times the diagonal or diameter of the substrate is the same as in the third aspect.

  According to the present invention, the following excellent effects can be obtained.

  By making the size of the temperature soaking plate cover the shape of the substrate as shown in FIG. 1 or FIG. 2, the temperature distribution during the growth of the periphery of the substrate can be made uniform. it can.

  Further, the gas flowing into the gap between the substrate and the susceptor is also reduced by bending the flow path, which is effective in improving the in-plane uniformity.

  Therefore, in the epitaxial growth using the MOVPE method, for example, the in-plane distribution of the p-type carrier concentration can be suppressed to 3% or less by using a temperature soaking plate capable of covering the shape of the semiconductor wafer. . By improving the in-plane uniformity of the peripheral portion of the wafer and improving the yield of semiconductor elements, there is an effect of increasing the usable area of the wafer.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

  The configuration of the premise vapor phase epitaxial apparatus is the same as that of FIG. 5 except for the relative structure of the temperature soaking plate and the susceptor. That is, a plate-shaped susceptor 1 is provided on the upper wall of the reaction tube 10 through which the source gas flows from the source gas introduction port 10a to the gas exhaust port 10b, and the susceptor 1 can be rotated by the motor 6 serving as a rotating means. Further, an opening 7 is formed in substantially the same shape as that of the semiconductor substrate 2 to be subjected to vapor phase epitaxial growth, the surface of the substrate 2 is accommodated in the opening 7 opened in the susceptor 1, and the lower surface is exposed inside the reaction tube. The temperature equalizing plate 4 is fitted into the opening 7 so as to face the heater 8 as a heating source for heating the substrate 2 and the susceptor 1 from above, and the temperature equalizing plate 4 is adjacent to the substrate 2. It is the composition made to do. Here, the substrate 2 is a semiconductor wafer, and the material of the temperature soaking plate 4 adjacent thereto is made of carbon.

  The relative structure of the temperature soaking plate 4 and the susceptor 1 according to this embodiment is shown in FIGS. FIGS. 1 and 2 are schematic cross-sectional views of the susceptor 1 and the temperature-uniforming plate 4.

<Embodiment 1>
In the first embodiment shown in FIG. 1, the temperature soaking plate 4 is thicker than the semiconductor wafer (substrate 2) and has a disk shape that is constant and has a larger area scale than the semiconductor wafer (substrate 2). Here, the temperature soaking plate 4 has an area of 1.25 to 2 times the substrate area or a length of 1.1 to 1.4 times the diameter of the substrate.

  On the other hand, the opening 7 of the susceptor 1 includes an inner circumference corresponding to the outer circumference of the semiconductor wafer (substrate 2), and a relatively small-diameter substrate housing portion 7a having a depth corresponding to the thickness of the semiconductor wafer (substrate 2). And an inner circumference corresponding to the outer periphery of the temperature soaking plate 4 and a relatively large-diameter soaking plate storage portion 7b having a depth substantially corresponding to the thickness of the temperature soaking plate 4 as a result. As shown in FIG.

  Therefore, as shown in FIG. 1, in the opening 7 of the susceptor 1, the temperature equalizing plate 4 is placed on the semiconductor wafer (substrate 2) and the step 71 that is flush with the semiconductor wafer (substrate 2). 2) The temperature soaking plate 4 having a larger area scale is covered.

  In this way, the temperature distribution during the growth of the peripheral portion of the semiconductor wafer (substrate 2) can be made uniform by making the shape so that the temperature soaking plate 4 covers the shape of the semiconductor wafer (substrate 2). .

<Embodiment 2>
FIG. 2 shows a second embodiment. In this embodiment, the temperature soaking plate 4 includes a contact surface portion 4a having the same shape and dimension as the back surface of the substrate 2, and a soaking plate portion 4b which is a portion above the contact surface portion 4a. The soaking plate portion 4b is thicker than the semiconductor wafer (substrate 2) and has a constant and larger area than the semiconductor wafer (substrate 2), and the bottom surface of the soaking plate portion 4b ( A contact surface portion 4 a having the same shape and dimension as the back surface of the substrate 2 is provided so as to project from the surface on the substrate side. Here, the soaking plate portion 4b has an area of 1.25 to 2 times the substrate area or a length of 1.1 to 1.4 times the diameter of the substrate.

  On the other hand, the opening 7 of the susceptor 1 has a depth corresponding to the inner circumference corresponding to the outer circumference of the semiconductor wafer (substrate 2) and the sum of the thickness of the semiconductor wafer (substrate 2) and the thickness of the contact surface portion 4a. Relatively large-diameter soaking having a relatively small-diameter substrate housing portion 7c, an inner circumference corresponding to the outer periphery of the soaking plate portion 4b, and a depth substantially corresponding to the thickness of the soaking plate portion 4b. As a result, it has a step cross-sectional shape having a step 72 in the middle in the thickness direction.

  Therefore, as shown in FIG. 2, in the opening 7 of the susceptor 1, the temperature equalizing plate 4 is housed with its peripheral portion placed on the step 72. That is, the temperature soaking plate 4 is placed on the conductor wafer (substrate 2) via the contact surface portion 4a, and the temperature soaking plate 4 having a larger area scale is covered on the conductor wafer (substrate 2). At this time, the lower surface of the peripheral edge portion of the soaking plate portion 4b is brought into close contact with the step 72, and the contact surface portion 4a is brought into close contact with the conductor wafer (substrate 2).

  In this way, by making the size of the temperature soaking plate 4 to have a shape that covers the shape of the substrate, the temperature distribution during the growth of the peripheral portion of the substrate can be made uniform. Further, the lower surface of the peripheral edge of the soaking plate portion 4b is brought into close contact with the step 72, and the contact surface portion 4a is brought into close contact with the semiconductor wafer (substrate 2), so that the gas flow path between the substrate 2 and the susceptor 1 is blocked or closed. Since it is bent, the disturbance of the gas flow flowing through the reaction tube 10 can be reduced, and the in-plane uniformity of crystals in the conductor wafer (substrate 2) can be improved.

  In the above embodiment, the temperature soaking plate 4 is configured to have an area that is 1.25 to 2 times the area of the substrate. However, when the substrate is rectangular, 1.1 to 1.4 of the diagonal of the substrate. By installing a temperature soaking plate having a double length on the substrate, a similar crystal homogenization effect within the substrate surface can be exhibited.

  The horizontal vapor phase epitaxial growth apparatus of the present invention can be applied to all devices that require in-plane uniformity in epitaxial growth using the MOVPE method. Further, as shown in FIG. 4, the structure of the soaking plate fusion susceptor 5 in which the susceptor and the temperature soaking plate are united and integrated is considered to have an in-plane uniformity effect.

It is a longitudinal cross-sectional view which shows the relative structure part of the temperature soaking plate and susceptor in the vapor phase epitaxial growth apparatus which concerns on 1st embodiment of this invention. It is a longitudinal cross-sectional view which shows the relative structure part of the temperature uniform plate and susceptor in the vapor phase epitaxial growth apparatus which concerns on 2nd embodiment of this invention. It is a longitudinal cross-sectional view which shows the modification of the relative structure part of a temperature uniform plate and a susceptor. It is a longitudinal cross-sectional view which shows the relative structure part of the temperature uniform plate and susceptor in the conventional vapor phase epitaxial growth apparatus. It is a longitudinal cross-sectional view which shows the vapor phase epitaxial growth apparatus of a prior art. It is the figure which showed the main reactor systems of the conventional vapor phase epitaxial growth apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Susceptor 2 Board | substrate 3 Inward claw 4 Temperature soaking plate 4a Contact surface part 4b Soaking plate part 7 Opening
7a, 7c Substrate storage part 7b, 7d Soaking plate storage part 71, 72 Step 8 Heater (heating means)
10 reaction tubes

Claims (6)

A susceptor provided facing the inside of the reaction tube and having an opening for storing and supporting the substrate with the front side of the substrate facing the reaction tube, and a back side of the substrate received and supported in the opening of the susceptor A horizontal vapor phase epitaxy growth apparatus provided with a temperature soaking plate provided with heating means for heating the substrate, the temperature soaking plate and the susceptor,
A vapor phase epitaxial growth apparatus characterized in that, as the temperature soaking plate, a temperature soaking plate having a shape covering the substrate is provided on the substrate. The vapor phase epitaxial growth apparatus according to claim 1,
A vapor phase epitaxial growth apparatus characterized in that a temperature soaking plate having an area of 1.25 to 2 times the substrate area is provided on the substrate. The vapor phase epitaxial growth apparatus according to claim 1,
A vapor phase epitaxial growth apparatus characterized in that a temperature soaking plate having a length 1.1 to 1.4 times the diagonal or diameter of a substrate is provided on the substrate. A susceptor provided facing the inside of the reaction tube and having an opening for storing and supporting the substrate with the front side of the substrate facing the reaction tube, and a back side of the substrate received and supported in the opening of the susceptor In a vapor phase epitaxial growth apparatus comprising a temperature soaking plate provided and heating means for heating the substrate, the temperature soaking plate and the susceptor,
A vapor phase epitaxial growth apparatus characterized in that, as the temperature soaking plate, a temperature soaking plate having a contact surface portion having the same shape as the substrate and a soaking plate portion shaped so as to cover the substrate is provided on the substrate. . The vapor phase epitaxial growth apparatus according to claim 4, wherein
A vapor phase epitaxial growth apparatus, characterized in that a temperature soaking plate having a contact surface portion having the same shape as a substrate and having an area of 1.25 to 2 times the substrate area is disposed on the substrate. The vapor phase epitaxial growth apparatus according to claim 4, wherein
Vapor phase epitaxial growth, characterized in that a contact surface portion has the same shape as that of the substrate, and a temperature soaking plate having a length 1.1 to 1.4 times the diagonal or diameter of the substrate is provided on the substrate. apparatus.

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