JPH0456799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a susceptor for a vapor phase growth apparatus such as epitaxial or CVD.

[Prior art]

An example of a conventional susceptor in a vertical type of such a vapor phase growth apparatus will be described with reference to FIG. The susceptor 11 is usually made of carbon and has a circular shape with a thickness of 10 mm to 30 mm, and the central hole 12 is a hole into which a rotating shaft (not shown) and a reaction gas supply pipe are inserted, and a plurality of recesses 13 (not shown) on the top surface are inserted. A wafer is placed on the susceptor, and the wafer is further heated by a high frequency coil 14, and the temperature of the wafer is raised mainly by heat conduction from the susceptor. At this time, it is important to raise the temperature of the multiple wafers to a uniform temperature within the plane, and the temperature distribution within the wafer plane is controlled by the susceptor 11.
Susceptor 1 because it strongly depends on the in-plane temperature distribution
Uniform temperature distribution within one plane is essential.

In the case where the high frequency coil 14 is provided on the lower surface of the susceptor 11 as shown in FIG. By rotating the susceptor 11, the temperature distribution in the circumferential direction of the susceptor 11 is made uniform. In this case, the susceptor 11 is heated by the induced current, and in order to obtain a good temperature distribution, it is important to improve the heat conduction in the direction of the susceptor surface. It is necessary to make it above a certain value.
Increasing the thickness of the susceptor 11 increases the capacity of the thermal power source, that is, the high-frequency coil 14, increasing energy costs, and increases the time required to raise and lower the temperature of the susceptor 11, resulting in an increase in sequence time and a decrease in productivity. There were flaws.

[Purpose of the invention]

The present invention was made from this point of view, and its purpose is to make the temperature distribution uniform within the surface of the susceptor without increasing the thickness of the susceptor.
It is an object of the present invention to provide a susceptor for a vapor phase growth apparatus that improves the quality of the product, saves energy, and shortens the time for raising and lowering the temperature to increase productivity.

[Key points of the invention]

The susceptor for a vapor phase growth apparatus of the present invention is characterized by comprising two carbon plates, an upper and a lower carbon plate, and a thermally defective conductive band for transmitting infrared rays is interposed between the two plates.

[Embodiments of the invention]

FIG. 1, which shows one embodiment of the present invention, will be described below. The susceptor 21 is the conventional susceptor 1
1, the lower carbon plate 22 has approximately the same diameter but 1/2 or 1/3 the thickness, and the upper carbon plate 2 has approximately the same shape as the lower carbon plate 22.
It is divided into two pieces, 3 and 3. Upper carbon plate 2
3 is placed on the lower carbon plate 22 by a ring-shaped support 24 on the outer periphery and a ring-shaped support 25 on the inner periphery, and there is a relatively narrow airtight space between the carbon plates 22 and 23. A space 26 is formed. The supports 24 and 25 described above may be thermally poor conductors, may be integrated with either of the carbon plates 24 and 25, may be provided only on one side of the outer circumference or the inner circumference, and Instead of a ring shape, the shape may be a partial shape obtained by dividing a ring. Note that 12 is a hole into which a rotating shaft (not shown) is inserted, 13 is a recessed portion on which a wafer (not shown) is placed, and 14 is a high frequency coil. In such a susceptor 21, when the lower carbon plate 22 is induction-heated by the high-frequency coil 14, infrared radiation is scattered from the entire surface of the lower carbon plate 22 with a substantially uniform distribution, and the upper carbon plate 23 is heated. This is absorbed and heated evenly. In this way, the process of increasing the temperature of the upper carbon plate includes the first stage in which the lower carbon plate 22 is directly heated by the high-frequency coil 14, and then the radiant light from the lower carbon plate 22 and both carbon plates 22 and The second stage is heating of the upper carbon plate 23 by indirect heat conduction by the gas of the thermally poor conductor existing in the space 26 between the carbon plates 23 and 23. The heat uniformity inside the room is greatly improved.

FIG. 2 shows a second embodiment of the present invention. A susceptor 31 has a lower carbon plate 32 which has a slightly larger diameter and 1/2 to 1/3 thickness than the conventional susceptor 11. The upper carbon plate 33 has a slightly smaller diameter and the same thickness as the lower carbon plate 32.
It is divided into two pieces. In order to reduce direct heat transfer between the two carbon plates 32 and 33, pin-shaped supports 34 made of quartz, which is a poor thermal conductor, are inserted into each of them, so that the upper carbon plate 33 is connected to the lower carbon plate 32. A relatively narrow space 35 is formed between the two carbon plates 32 and 33. Furthermore, this space 35
If a quartz plate (not shown), which allows infrared rays to pass through but is a poor thermal conductor, is inserted into the space 26 of the first embodiment, the radiation from the lower carbon plates 22 and 32 to the upper carbon plates 23 and 33 will be reduced. The light does not decrease, and the lower carbon plates 22 and 32 are connected to the upper carbon plate 2 by slow heat conduction through the quartz plate.
3, 33 is added, the heat uniformity of the upper carbon plates 23, 33 is improved, and the heat capacity of the upper carbon plates 23, 33 is indirectly increased, resulting in an increase in thermal stability. do.

[Effect of return]

As explained above, in the susceptor for a vapor phase growth apparatus of the present invention, by dividing the susceptor into upper and lower parts, the lower carbon plate is heated first, and then the upper carbon plate on which the wafer is placed is heated, and then the lower carbon plate is heated. It is indirectly heated by radiant heat emitted from the plate in a scattered manner. Therefore, the thermal uniformity of the upper carbon plate is improved, and as a result, slip defects in vapor phase growth are greatly reduced, and the uniformity of the film thickness, resistivity, etc. of the vapor phase growth layer is also improved. Furthermore, since the susceptor is substantially thinner than the conventional one, it has a small heat capacity and saves energy.Furthermore, since the upper susceptor is thin, the temperature drop time is shortened, and the cycle time can be shortened, which has the advantage of increasing productivity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of another embodiment of the invention, and FIG. 3 is a sectional view of a conventional example. 22, 32... lower carbon plate, 23, 33...
...Upper carbon plate, 24, 25, 34... Support body, 26, 35... Space (thermal failure guide zone).

Claims (1)

[Scope of Claims] 1. A susceptor for a vapor phase growth apparatus, which is made up of two carbon plates (upper and lower), with a thermally conductive band for transmitting infrared rays interposed between the two plates. 2. The susceptor for a vapor phase growth apparatus according to claim 1, wherein the thermal failure guide zone is a space. 3. The susceptor for a vapor phase growth apparatus according to claim 1, wherein the thermal failure guide zone is a quartz plate. 4. The gas phase according to claim 2, characterized in that the entire circumference or a part of only the outer periphery and/or inner periphery of the lower carbon plate and the upper carbon plate are in contact with each other via a support. Susceptor for growth equipment. 5. The susceptor for a vapor phase growth apparatus according to claim 2, wherein the upper carbon plate is placed on the lower carbon plate via a support made of a thermally poor conductor.