JPS6285424A - Vapor growth apparatus - Google Patents

Abstract

PURPOSE:To form a sharp hetero boundary by feeding gas stream flow in a reaction tube in a laminar layer, thereby switching gas in a short time. CONSTITUTION:The height of a quartz reaction tube 5 is held constantly to a susceptor range 54 after smoothly enlarging near a gas supply port 51. The width is smoothly enlarged from the vicinity of the port 51 to the range 54. An auxiliary member 6 is fed into the tube 5 to uniformize the gas flowing passage section from the range 54 of the tube 5 to a gas exhaust port 52. In order that a susceptor 2 may be charged and removed from the range 54 to the exhaust port 52, it is necessary to set the section the same as the range 54. Thus, since the sectional are of the gas flowing passage largely varies, this prevents the variation.

Description

[Detailed Description of the Invention] [Summary] This is a vapor phase growth apparatus in which the gas flow cross section is made uniform from the gas supply port to at least the susceptor region or the substrate region into which the substrate is charged, and the gas flow is laminar. . Furthermore, preferably, the vapor phase growth apparatus is such that the gas flow cross section is made uniform over the entire region of the reaction tube, including from the susceptor region or the substrate region to the gas outlet. As a result, in particular, gas switching becomes possible sharply, and Peter interface separation becomes possible accurately.

[Industrial application field]

The present invention relates to a vapor phase growth apparatus. In particular, in vapor phase growth equipment that may switch between reactive gases,
Concerning structural improvements that enable sharp gas switching.

[Conventional technology]

FIG. 2 shows the configuration of an example of a conventional vapor phase growth apparatus. In the figure, l is a quartz reaction tube, 2 is a susceptor on which the substrate 3 is placed, and 4 is a heating device. While the heating device 4 is operated to maintain the temperature of the substrate 3 at a desired temperature, a reactive gas is supplied from the gas supply port 1 of the quartz reaction tube 1, and brought into contact with the substrate 3 to cause a growth reaction. , the used gas is discharged from the gas outlet 12.

[Problem that the invention seeks to solve]

Generally, the cross-sectional area of the gas flow path rapidly expands at the gas supply port 1 of the quartz reaction tube 1, so the gas flowing into the quartz reaction tube 1 becomes turbulent at the gas supply port 1. , as a result, the gas supply port 1] and the susceptor region 13
Gas stagnates between the

However, this does not cause any noticeable problems in practice when the reactive gases used are not switched during the vapor phase growth (when a single type of material is grown).

However, when the reaction gas is switched during vapor phase growth (when a hetero interface is formed), as a result of the gas retention, the gas composition in the susceptor region 13 changes after the gas is switched at the gas supply port 1]. It will take a considerable amount of time, eg, 1 whole culm degree, for the change to stabilize. This is not a big problem when the growth rate is extremely slow, but since the growth rate in the semiconductor vapor phase growth process is generally several angstroms per second or more,
This results in a growth of 0 Å or more, which exceeds the allowable limit for the manufacturing process of semiconductor devices.

The purpose of the present invention is to eliminate this drawback, and to sharply switch gases even when it is necessary to switch reactive gases during vapor phase growth, such as when forming a heterointerface.
An object of the present invention is to provide a vapor phase growth apparatus capable of forming a sharp hetero-interface.

[Means for solving problems]

The means taken by the present invention to achieve the above object is that the structure of the reaction tube 5 of the vapor phase growth apparatus is changed from the gas supply port 51 to the susceptor area 5 where the susceptor 2 on which the substrate 3 is placed.
4, the cross section of the gas flow path gradually expands to have the same shape as the cross section of the gas flow path on the susceptor 2.

Furthermore, if an auxiliary member 6 is used to make the cross section of the gas flow uniform from the susceptor region 54 to the gas discharge port 52, the effect will be further improved.

[Effect]

The above drawbacks can be overcome if the gas flow becomes laminar at least in the area from the gas supply port to the susceptor area, so the cross section of the gas flow in this area is made uniform.

As a result, the gas does not stagnate in the region from the gas supply port to the susceptor region, and when the gas is switched, the gas quickly changes and becomes stable in the susceptor region. According to the results of experiments, the change is completed in about 1 to 2 seconds, and the growth thickness during that period is several amps, which is within an acceptable range for a semiconductor device manufacturing process.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vapor phase growth apparatus according to an embodiment of the present invention will be further described below with reference to the drawings.

1A is a side view, and FIG. 1A is a plan view. 5
is a quartz reaction tube, and as is clear from the side view, its height gradually expands near the gas supply port 51 and then remains constant up to the susceptor region 54. Also, its width is
As is clear from the plan view, it gradually expands from the vicinity of the gas supply port 51 to the susceptor region 54. 2 is a susceptor, and the substrate 3 is placed on it. A heating device 4 heats the inside of the quartz reaction tube 5. 6 is an auxiliary member, which connects the gas outlet 52 from the susceptor region 54 of the quartz reaction tube 5.
The quartz reaction tube 5 is placed in the quartz reaction tube 5 in order to make the cross section of the gas flow path uniform. Gas discharge r352 from the susceptor area 54
In order to enable loading and unloading of the susceptor 2,
This is to prevent the cross-section of the gas flow path from changing significantly since it is necessary to make the cross-section the same as that of the susceptor region 54. Reference numeral 53 denotes an opening portion for allowing the charging portion of the susceptor 2 and the auxiliary member 6 to be taken out.

Since the cross section of the gas flow flowing through the quartz reaction tube of the vapor phase growth apparatus according to the embodiment of the present invention having the structure described above is generally uniform, the gas flow becomes a laminar flow, and no gas stagnation occurs. , changes without delay when switching the reactant gas. As a result, a sharp heterointerface is formed.

〔Effect of the invention〕

As explained above, in the reaction tube of the vapor phase growth apparatus according to the present invention, the cross section of the gas flow path gradually expands from the gas supply port toward the susceptor region where the susceptor on which the substrate is placed is inserted. As a result, the gas flow flowing through the reaction tube is generally laminar, and no gas stagnation occurs near the gas inlet.Therefore, when this vapor phase growth apparatus forms a hetero interface, Even when it is necessary to switch the reactant gas during the iso-vapor phase growth, the gas can be switched in a short time (1 to 2 seconds according to experimental results), and a sharp heterointerface can be formed.

[Brief explanation of drawings]

FIG. 1a is a side view of a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 1 is a plan view of a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a vapor phase growth apparatus according to the prior art. DESCRIPTION OF SYMBOLS 1...Quartz reaction tube in prior art, 1]...Gas supply port (prior art), 12...Gas discharge port (prior art), 13...Fist susceptor area (prior art), 2
... Susceptor, 3. Substrate, 4. Heating device, 5. Quartz reaction tube according to the present invention, 51.Φ.
Gas supply port (present invention), 52... Gas discharge port (present invention), 53... Opening part (present invention), 54... φ susceptor area (present invention), 6... Auxiliary member.

Claims (1)

[Claims] [1] The cross section of the gas flow path is gentle from the gas supply port (51) toward the susceptor area (54) where the susceptor (2) on which the substrate (3) is placed is loaded. expanded to the susceptor (
2) A vapor phase growth apparatus having a reaction tube (5) having the same shape as the cross section of the gas flow path above. [2] According to claim 1, an auxiliary member (6) is installed to make the gas flow cross section uniform from the susceptor region (54) of the reaction tube (5) to the gas outlet (52). vapor phase growth equipment.