JPS61127696A - Vapor phase reactor - Google Patents

Abstract

PURPOSE:To grow plural wafers having a uniform composition in a vapor phase by rotating a stand carrying the wafers thereon and which is inclined to the flow of a gaseous reactant around its axis, and simultaneously revolving the stand around a rotating shaft. CONSTITUTION:A gaseous reactant is introduced from a supply port 12, and discharged into a discharge port 13 while forming a flow with the axial center of a reaction tube 11 as the center. A rotating shaft 14 which is freely rotatable with the axial center of the reaction tube 11 as the center is provided, and rotated by a driving motor 15. Plural discoid stands 17 on which a wafer 16 is set are furnished around the upper end of the rotating shaft 14, and made freely rotatable with the axial center of each stand 17 as the center. Each stand 17 is arranged at equal angles to the axial center of the revolving 14, and arranged at the angle (theta) of about 10-80 deg. to the axial center of the revolving shaft 14. Since a boss 19 provided on the rear surface of the stand 17 is fitted to a columnar shaft 18 provided on the outer periphery of the rotating shaft 14, each stand 17 is revolved around the shaft 14 by the rotation of the rotating shaft 14. Each stand 17 rotates around its axis along with the revolution around the shaft 14 by the meshing of a bevel gear 20 on the outer peripheral surface of the stand 17 with a crown gear 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to vapor phase reaction equipment, for example, vapor phase epitaxial growth applied to manufacturing processes of various semiconductor devices, particularly MOCV
D (Metalorganic Cheslcal
The present invention relates to a gas phase reactor suitable for use in Vapor Depo-sltlon.

[Conventional technology]

Conventionally, a gas phase reactor used for vapor phase epitaxial growth such as MOCVD, for example, as shown in FIG. A support base (3), a so-called susceptor, for supporting a wafer (2), that is, a substrate to be grown by vapor phase epitaxial growth, is arranged along the air flow of the source gas in the wafer 11. 3) is heated to heat the wafer (2) to a required substrate temperature, and a desired epitaxial growth layer, such as a compound semiconductor layer, is formed on the wafer (2) by a thermal decomposition reaction of the raw material gas that passes in contact with the wafer. is grown in vapor phase. Or similarly as shown in Figure 3,
For example, a vertical reaction tube (11, i.e., a bell jar) made of a quartz tube is provided, and the raw material gas is fed downward from above, and the wafer (2) is placed in a horizontal plane so as to be almost directly opposite to the air flow of the raw material gas. A gas phase reaction apparatus is used in which a support stand (3), that is, a susceptor is arranged and rotated in a horizontal plane.

[Problem that the invention seeks to solve]

However, when using a gas phase reactor as described above,
A drawback is that it is difficult to perform uniform vapor phase growth on the wafer.

That is, in the horizontal structure shown in FIG. 2, since the wafer is arranged almost along the source gas airflow, there is a difference in the vapor growth rate between the upstream and downstream portions of the source gas airflow on the wafer. The difference becomes particularly noticeable as the number of wafers increases.

Furthermore, even when using the vertical rotation method explained in FIG. 3, there may be a difference in the vapor phase growth rate in the radial direction of the support, or non-uniformity may occur in the composition of the grown layer. There is a problem with this.

The present invention has made it possible to effectively solve these problems, that is, to form a vapor phase growth layer having uniform vapor phase growth and a uniform composition on a plurality of wafers and on each wafer. The purpose of the present invention is to provide a gas phase reactor capable of performing the following steps.

[Means for solving the problem] In the present invention, a reaction gas, that is, a raw material gas, is fed into a reaction tube, for example, a vertical bell jar, from above to below, and the main flow direction is, for example, approximately vertical. forming a reactant gas flow.

Then, a plurality of supports, that is, susceptors, on which the substrates to be subjected to vapor phase growth, that is, wafers, are placed are placed at a required angle without being perpendicular to or parallel to the main flow direction of the reaction gas. The gas flow is arranged concentrically around the approximate central axis of the gas flow. On the other hand, in relation to this support stand, a means is provided to maintain each support stand at the above-mentioned inclination, that is, to rotate or rotate the support stand along the wafer mounting surface, and the relative arrangement of all the support stands is provided. A means is provided for rotating or revolving the plurality of supports as a whole while maintaining the above-mentioned inclination.

[Effect]

As described above, according to the gas phase reaction apparatus according to the present invention, the wafer support stands rotate on their own axis with a required inclination with respect to the flow of the reaction gas, and the wafers on each support stand are caused to revolve as a whole. Since each part comes into contact with the flow of reactant gas under uniform conditions, its growth rate,
and the composition can be uniform throughout the wafer and in each part of each wafer.

〔Example〕

An example of a gas phase reactor according to the present invention will be explained with reference to FIG. In the present invention, a vertical reaction tube (11) made of, for example, a quartz bell jar is provided, a reaction gas supply port (12) is provided at the upper end approximately on the axis, and a discharge port (13) is provided below, for example, on the side. ) will be established.

In this way, for example, a main flow of reaction gas is formed approximately centered on the axis of the reaction tube (11).

A rotating shaft (14) is provided along this axis, that is, on the axis of the flow of the reaction gas along the vertical direction, in other words, on the axis of the reaction tube (11), which is rotatably supported around this axis. . (15) indicates a drive motor that rotationally drives this rotating shaft (14).

Around the upper end of the rotating shaft (14) are wafers (16
), for example, three disc-shaped support stands (
17) So-called susceptors are each rotatably supported around the central axis of the support base (17).

Each support stand (17) is arranged at equal angular intervals with respect to the rotation axis (14). For example, when three supports (17) are provided, these supports (17) are arranged at angular intervals of 120° with respect to the rotation axis (14). Each support stand (1
7) are arranged so that each wafer mounting surface thereof is directed toward the inner wall surface of the reaction tube (11), and the wafers are inclined toward each other downwardly. That is, each support table (17) has its plate surface direction, that is, the wafer mounting surface parallel and perpendicular to the main flow direction of the airflow, that is, the vertical direction, and therefore to the central axis of the rotating shaft (14). For example, the angle θ is 80° to 10°. The rotational support of each of these support stands (17) with respect to the rotation shaft (14) is achieved by, for example, using a cylindrical recess provided on the back surface of the support stand (17) on a cylindrical shaft (18) protruding from the outer periphery of the rotation shaft (14). Boss with (
19), it can be rotatably supported. In connection with these supports (17), means for rotating them is provided. This rotation means, for example, forms a bevel gear (20) on the outer peripheral surface of each disc-shaped support stand (17),
On the other hand, the crown gear (21) meshing with these, respectively, is connected to the rotating shaft (
14), concentrically therewith, and in a horizontal plane orthogonal to the rotation axis (14).

(22) is a high frequency coil which is heated by induction heating of the support base (17) by passing high frequency electricity through it.
) to the required gas temperature.

The rotating shaft (14), crown gear (21), support stand (17), etc. arranged in the reaction tube (11) are made of quartz, graphite, ceramic, or SiC, which do not emit impurity gases and have excellent heat resistance. Consisted of. Support stand (1
7) can be integrally molded as a whole together with the bevel gear (17) provided on its outer periphery, or the support stand (17)
) may be made of different materials from the support surface for supporting the wafer (16) and the bevel gear (20) on the outer periphery, and various configurations may be taken, such as by combining the two. In addition, when the boss (19) of the support base (17) and the shaft (18) of the rotating shaft (14), especially the shaft (18) protruding from the support base (17), are made of graphite, the sliding of both, and therefore the support base ( 17
) can be rotated smoothly.

In the above-described gas phase reaction apparatus according to the present invention, when performing a gas phase reaction such as vapor phase growth of a compound semiconductor ^lGaAs, a reaction gas, that is, a raw material is supplied from the supply port (12) together with a carrier gas such as H2 gas. Gases such as trimethylaluminum, trimethylgallium, and arsine are fed at predetermined ratios. In this way, the airflow is brought into contact with the susceptor, that is, the wafer on the support base (17), and in this case, the drive motor (
15) to rotate the rotating shaft (14). In this way, by the rotation of the rotating shaft (14), all the supporting stands (17) supported by the rotating shaft (14) rotate and revolve around the rotating shaft (14) while maintaining their mutual positional relationship.

In other words, this rotating shaft (14) becomes a revolution means. Along with this, along with this revolution, the crown gear (21) and the bevel gear on the peripheral surface of the support base (17) mesh with each other, so that the support base (17)
) rotate around their central axes. Therefore, since the wafer (16) supported on the support stand (17) rotates on its own axis and around the axis of the reaction tube (11), the wafer (16) supported on the support stand (17) rotates on its own axis and around the axis of the reaction tube (11). Each part of 16) will be in contact with the flow of reactant gas under virtually identical conditions.

Note that one wafer (16) can be placed on the support table (17), or a plurality of wafers can be arranged on the support table (17).

〔Effect of the invention〕

As described above, in the present invention, the wafer (16) rotates and revolves within the reaction tube (11), so that all the wafers (16) and the entire area of each wafer are uniformly contacted with the reaction gas. Therefore, unevenness in reaction rate and composition can be effectively avoided. Further, according to the present invention described above, the support stand (17
) The mounting surface of the wafer (16), that is, the surface of the wafer (16), is arranged so that it does not directly face the flow of the reaction gas, thereby ensuring that gas stagnation does not occur on the surface of the wafer (16) at all times. Since vapor phase growth can be performed while being in contact with a new reaction gas, it is possible to avoid problems such as the generation of polycrystals during epitaxial growth, for example.

Further, according to the above-mentioned example, the heating temperature of the support stand (17) tends to be high at the outer circumferential part near the heating coil (22), but when the support stand (17) has the above-mentioned configuration, The bevel gear (20) meshes with the crown gear (21) at the outer periphery and heat is dissipated from this, so the temperature difference between the center and outer periphery of the support base (17) is kept relatively small. This has the further advantage that the gas phase reaction, eg, vapor phase epitaxial growth, takes place uniformly.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an example of a gas phase reactor according to the present invention, and FIGS. 2 and 3 are line configuration diagrams of each side of a conventional gas phase reactor. (11)...Reaction tube, (14)... Rotating shaft, (
17)...Support stand, (16)...Wafer, (
20)...Bevel gear, (21)...Crown gear. Figure 2 Figure 3

Claims (1)

[Claims] A plurality of support stands on which wafers are placed, means for rotating each support stand with a required inclination with respect to the flow of the reaction gas, and means for causing the plurality of support stands to revolve as a whole. A gas phase reactor comprising: