JPH06349748A - Vapor growth device for semiconductor - Google Patents

Abstract

(57) [Summary] [Structure] A plurality of semiconductor substrates 4 are attached to the rotary shaft 3 in the reaction tube 1.
In a semiconductor vapor phase growth apparatus that revolves at a speed of 500 rpm or more and 2000 rpm or less, the susceptor 8 in which the circumferential direction side is positionally higher than the rotation axis side and the inclination angle is 1 ° or more and 15 ° or less. Vapor deposition apparatus for arranging the semiconductor substrate on the inclined surface of the. [Effect] It becomes possible to form a crystal thin film with good uniformity on the entire surface of a plurality of semiconductor substrates processed at the same time.
Directly connected to productivity improvement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor vapor phase growth apparatus for simultaneously processing a plurality of semiconductor substrates.

[0002]

2. Description of the Related Art An example of a conventional semiconductor vapor phase growth apparatus is shown in FIG.
Shown in. In FIGS. 4A and 4B, 1 is a reaction tube having an inner diameter of 23 cm made of quartz or the like, 2 is a susceptor having a diameter of 150 mm made of carbon or the like for holding a growth substrate,
3 is a rotating shaft for rotating the susceptor, 4 is a substrate to be grown having a diameter of 50 mm placed on the susceptor, 5 is a heater made of carbon or the like for heating the susceptor, and 6 is a support base of the heater. is there. In this example, the susceptor 2 on which the growth substrate 4 is placed is heated to 500 to 700 ° C. by the heater 5, and the susceptor 2 is set to 10 to 5 by the rotating shaft 3.
While rotating at 0 rpm, a semiconductor thin film having a film thickness of several μm or less is formed on the substrate 4 to be grown by utilizing the thermal decomposition of the raw material gas. As shown in FIG. The substrate 4 is placed substantially horizontally in the groove formed on the susceptor 2. This example is a semiconductor vapor phase growth apparatus for processing four growth substrates at the same time and is intended for mass production. Therefore, the crystal film thickness in the plane of the growth substrate, the composition in the crystal, etc. Are required to be uniform, and the characteristics such as film thickness and composition of the semiconductor thin films formed on the four growth substrates to be processed at the same time must be the same. Rotation of the susceptor is performed to achieve these uniformity, and optimization of manufacturing conditions such as rotation speed, pressure in the reaction furnace, gas supply amount to the reaction furnace, heating temperature, etc. Is done.

[0003]

However, in spite of the setting of such manufacturing conditions, in the semiconductor vapor phase epitaxy apparatus for horizontally mounting a growth substrate as shown in FIG. A distribution occurs in the characteristics of the semiconductor thin film formed on the substrate. For example, when an InP crystal film is formed on an InP substrate by a MOCVD method using TMIn (trimethylindium) and PH ₃ (phosphine) as raw materials under the conditions of a reactor pressure of 76 torr and a total gas flow rate of 30 l / min, Taking the film thickness as an example, as shown in FIG. 4C, the film thickness tends to gradually decrease from the rotation center of the susceptor in the circumferential direction of the susceptor. Even if the conditions are adjusted, for example, diameter 50
The film thickness distribution on the growth substrate of mm reaches 5 to 10%. Further, other than the film thickness, for example, the crystal composition and the distribution of impurities in the crystal also change in the circumferential direction of the susceptor from the rotation center of the susceptor like the film thickness, so that it is necessary to improve the uniformity for mass production. There is.

On the other hand, the apparatus shown in FIG. 3 has been developed in relation to such problems. Here, as shown in FIG. 3A, the semiconductor substrate is provided with an inclination angle of about 30 ° to prevent the substrate from dropping due to the centrifugal force generated by the rotation of the susceptor 7, and the susceptor is operated at a high speed of 1000 rpm. Aiming for homogenization by rotating. However, here, as shown in FIG. 3B, the semiconductor thin film also shows a non-uniform cross-sectional film thickness distribution.
Although the distribution shape is changed from (c), the film thickness still tends to decrease in the outer peripheral direction of the susceptor. Further, according to this device, a new problem that the number of defects on the surface of the crystal film is increased occurs. This is considered to be caused by the generation of vortices in the raw material gas flow on the susceptor as shown in FIG. 3, the same symbols as those in FIG. 4 indicate the same things.

[0005]

As a result of various investigations in view of the above circumstances, the present inventors regulate the inclination angle of the susceptor within a specific range when the semiconductor substrate is revolved at a specific speed. As a result, it was found that the generation of the vortex of the gas flow as described above can be prevented and the uniformity of the film thickness can be remarkably enhanced, and the present invention has been completed based on this finding. That is, the present invention is a semiconductor vapor phase growth apparatus for revolving a plurality of semiconductor substrates in a reaction furnace about a rotation axis at a speed of 500 rpm or more and 2000 rpm or less, in which the circumferential side is positionally higher than the rotation axis side, Further, the present invention provides a semiconductor vapor phase growth apparatus characterized in that the semiconductor substrate is arranged on an inclined surface having an inclination angle of 1 ° or more and 15 ° or less.

[0006]

The present invention will be described in more detail based on the following examples. 1 (a) and 1 (b) show an embodiment of a semiconductor vapor phase growth apparatus of the present invention. In FIG. 1 (a), 8 is a susceptor, and as is clear from the cross-sectional view shown in FIG. 1 (b), the semiconductor substrate is mounted in a groove formed on the susceptor at an angle θ with respect to a horizontal plane. Placed. FIG. 1C is an example showing the result of vapor phase growth according to this example, and is formed on a growth substrate having a diameter of 50 mm by setting θ = 3 to 5 ° at a susceptor rotation speed of 1000 rpm. Thickness distribution of semiconductor thin film is 1-2
Found to improve within%, and at the same time,
The in-plane composition and the uniformity of the impurity concentration were also greatly improved. In FIG. 1, the same symbols as those in FIG. 4 indicate the same things. The most preferable range of the inclination angle θ depends on the material of the semiconductor thin film to be formed, the reactor pressure, the revolution speed, and the production conditions of the raw material gas supply amount. The relationship between the inclination angle θ and the film thickness distribution is shown in FIG. As shown in FIG. 2, when the tilt angle is less than 1 °, the contribution to the improvement of uniformity is extremely small, and from the vicinity of more than 15 °, the uniformity deteriorates and the quality of the crystal film tends to be impaired. Indicated. The reason for the latter is that, as shown in FIG. 3, by providing a steep slope, a hydrodynamic vortex is generated in the raw material gas flow in the reactor, and an unnecessary reaction such as a parasitic reaction in the raw material gas is generated. It is considered to be because of this and is not preferable. Therefore, it is necessary that the inclination angle θ is 1 ° or more and 15 ° or less, and preferably 4 to 12 °. In addition,
In the above embodiment, TMIn (trimethylindium) and PH ₃ (phosphine) are used as the raw materials, and the rotation speed of the susceptor is 1
Reactor pressure 76 torr at 000 rpm, total gas flow 3
InP on the InP substrate under the condition of 0 liter / min
The description was based on the case where the crystal film of 1 was prepared.

Needless to say, the present invention is not limited to the above-described embodiments, and various design changes can be made. Although the reaction tube is made of quartz in the examples, the present invention is not limited to the reaction tube made of other materials such as stainless steel, and the carbon heater used in the examples is a heating device. It is an example of the means, and selection of other heating means such as a high frequency induction heating method should be naturally taken into consideration in the reactor design. Although the susceptor is often made of carbon or the like, it is difficult in terms of mechanical strength and is often made of a metal material such as molybdenum.

[0008]

According to the present invention, it becomes possible to form a crystal thin film with good uniformity on the entire surface of a plurality of semiconductor substrates to be processed at the same time, which directly leads to improvement in productivity.

[Brief description of drawings]

FIG. 1 shows an embodiment of a semiconductor vapor phase growth apparatus according to the present invention, (a) is a perspective view showing an internal state, (b) is a sectional view of a susceptor, and (c) is a position of (b). 3 is a graph showing a cross-sectional film thickness distribution of a semiconductor thin film on a susceptor corresponding to FIG.

FIG. 2 is a graph showing a relationship between a tilt angle of a susceptor and a cross-sectional film thickness distribution.

FIG. 3 shows an example of a conventional semiconductor vapor deposition apparatus,
(A) is a schematic diagram represented by a cross-sectional view, and (b) is a graph showing a cross-sectional film thickness distribution of a semiconductor thin film on a susceptor in correspondence with (a).

FIG. 4 shows an example of a conventional semiconductor vapor phase growth apparatus,
(A) is a perspective view showing an internal state, (b) is a sectional view of a susceptor, and (c) is a graph showing a sectional thickness distribution of a semiconductor thin film on the susceptor corresponding to (b).

[Explanation of symbols]

 1 Reaction Tube 2, 7, 8 Susceptor 3 Rotating Shaft 4 Growth Substrate 5 Heating Heater 6 Heater Support

Claims (1)

[Claims] 1. A semiconductor vapor phase growth apparatus in which a plurality of semiconductor substrates are revolved around a rotation axis at a speed of 500 rpm or more and 2000 rpm or less in a reaction furnace, wherein a circumferential side is positionally higher than the rotation axis side, And this inclination angle is 1
A semiconductor vapor phase growth apparatus characterized in that the semiconductor substrate is arranged on an inclined surface of not less than 15 ° and not more than 15 °.