JPH06112140A - Exhaust pipe of single wafer vapor growth apparatus - Google Patents

Abstract

PURPOSE:To obtain the uniform flow of gas having reproducibilty for the gas, which is flowing in the reaction container in a single wafer vapor growth apparatus. CONSTITUTION:The cross-sectional shape of an exhaust pipe 6, which is connected to a reaction container 1, is made equal to the cross-sectional shape of the reaction container 1. A fine-tubing structure 7 comprising many fine tubes is arranged along the shape of an exhaust pipe 6 in the inside of the exhaust pipe 6 from a first straight-line part 6a to a second straight-line part 6c through a first bent part 6b of the exhaust pipe 6. The diameter, the cross-sectional shape, bending and the like of the exhaust pipe at the downstream side from the terminating end of the small-tubing structure, i.e., from the second straight-line part 6c, can be freely selected. The gas flowing on a substrate 2 is not disturbed by strightening action of the small-tubing structure 7, and the uniform flow having reproducibility can be obtained. Thus, the high-quality epitaxial thin film can be obtained. Since the vapor growth apparatus can be integrated into the compact configuration, the space of the apparatus is saved as the contribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vapor phase growth apparatus,
In particular, it relates to an exhaust pipe of a single-wafer vapor phase growth apparatus.

[0002]

2. Description of the Related Art In a vapor phase growth apparatus, a raw material gas is caused to flow in the vicinity of a substrate in a reaction vessel kept at an appropriate temperature, and silicon, compound semiconductor, etc. are deposited on the substrate by a thermal decomposition reaction or a hydrogen reduction reaction. Is an apparatus for growing a single crystal layer of. Among such devices, the single-wafer vapor phase growth device is a device that obtains a large-diameter and high-quality product by treating the substrates one by one.

[0003]

[Problems to be Solved by the Invention] In recent years, the diameter of the substrate has become remarkably large, and the required quality has become more and more strict. Vapor growth is carried out on the side of the raw material transport rate control, and therefore in order to obtain a uniform film quality, it is necessary to make the gas flow in the reaction vessel uniform and reproducible.
However, in the conventional vapor phase growth apparatus, although some devises have been made to the gas introduction port, no particular devise has been made to the gas discharge side, that is, the exhaust pipe. FIGS. 5 and 6 show an example of a conventional single-wafer type vapor phase growth apparatus, but the gas flowing over the substrate 2 and discharged from the reaction vessel 1 has a flowing direction of 90 degrees.
° and the flow path is significantly narrowed by the exhaust pipe 8, so the gas flow is significantly disturbed at this portion,
Since the exhaust pipe mounting position is close to the reaction container 1, the gas flow in the reaction container is also disturbed. In such a vapor phase growth apparatus, it is not possible to expect an ideal gas flow even if a precise adjustment mechanism is provided at the gas inlet and adjustment is performed with great care. Therefore, a dramatic improvement in film quality cannot be achieved. The present invention has been made in view of the above-mentioned conventional problems, and an exhaust pipe of a single-wafer vapor phase growth apparatus that can make a gas flowing in a reaction vessel a uniform and reproducible flow. It is intended to be provided.

[0004]

In order to achieve the above object, the exhaust pipe of the single-wafer vapor phase growth apparatus according to the present invention has a structure in which a substrate set in a reaction container of the single-wafer vapor phase growth apparatus is installed. It has a long shape in the same direction as the passing gas flow, and in such a configuration, the exhaust pipe has a cross-sectional area equal to that of the reaction vessel, or the exhaust pipe has a cross-sectional shape of the reaction vessel. The same as the cross-sectional shape, or
It is desirable that the exhaust pipe has a thin tube structure along the gas flow direction, and that the thin tube structure is detachable.

[0005]

Assuming an exhaust pipe having an infinite length and a uniform cross-sectional shape and a small pipe friction coefficient, the flow velocity distribution of the gas flowing through the exhaust pipe cross section at any position in the length direction of the exhaust pipe is It is equal to the flow velocity distribution of the gas flowing through the cross section of the exhaust pipe at another position. However, if the pipe diameter is expanded or reduced at any position in the length direction of the exhaust pipe, or if the exhaust pipe is bent, the gas flow is significantly disturbed upstream and downstream near these positions. This suggests that turbulence also occurs in the gas flow in the reaction vessel when the distance between the reaction vessel and these positions is short. Therefore, in claims 1 to 3 of the present invention, the exhaust pipe of the single-wafer vapor phase growth apparatus is assumed to have a long shape in the same direction as the direction of the gas flow passing over the substrate set in the reaction vessel. Since the cross-sectional area of the exhaust pipe or the cross-sectional shape of the exhaust pipe is made the same as the cross-sectional area or cross-sectional shape of the reaction vessel, it is possible to prevent the occurrence of gas flow turbulence in the reaction vessel.

[0006] However, in many single-wafer vapor phase growth apparatuses, there are many restrictions on the apparatus layout when the exhaust pipe is sufficiently long or the exhaust pipe is installed without bending as described above. Is difficult. Therefore, claim 4 of the present invention
In Nos. 5 and 5, since the thin pipe structure is provided inside the exhaust pipe along the gas flow direction, a rectifying action is produced by the thin pipe structure in the exhaust pipe. Therefore, no matter how the exhaust pipe diameter is changed or the exhaust pipe is bent on the downstream side of the thin tube structure, the rectification effect on the upstream side of the thin tube structure can be maintained. Further, when the thin pipe structure is provided in the bent portion of the exhaust pipe, in addition to the above-mentioned rectifying function, an effect of preventing the velocity vector of gas from becoming disordered due to the fact that the bending radius of the exhaust pipe is substantially reduced is added. It Since the thin tube structure is detachable, the exhaust pipe can be easily inspected and cleaned.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an exhaust pipe of a single-wafer vapor phase growth apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a schematic structure of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claims 1 and 2 is attached, and is set in a reaction vessel 1 of the single-wafer vapor phase growth apparatus. Base 2
The direction of the gas flowing above is indicated by an arrow. An exhaust pipe 3 having a shape elongated in the same direction as the gas flow is attached to the gas outlet of the reaction container 1. The cross-sectional area of each part of the exhaust pipe 3 is manufactured to be equal to the cross-sectional area of the reaction container 1, and the gas flowing in the reaction container 1 is exhausted to the outside of the system by the exhaust pump through the exhaust pipe 3.

FIG. 2 is a perspective view showing a schematic structure of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claim 3 is attached. The exhaust pipe 4 has the same sectional shape as that of the reaction vessel 1. The exhaust pipe is long along the direction of the gas flow. The exhaust pipe according to claims 1 to 3 is applied when the installation space of the single-wafer vapor phase growth apparatus is relatively large.

FIG. 3 is a perspective view showing a schematic structure of a first embodiment of a single-wafer vapor phase growth apparatus having an exhaust pipe attached thereto according to a fourth embodiment, in comparison with an installation space of the single-wafer vapor phase growth apparatus. It is applied when there is a margin. The cross-sectional shape of the exhaust pipe 4 is the same as the cross-sectional shape of the reaction vessel 1. Inside the exhaust pipe 4, a thin tube structure 5 made up of a large number of thin tubes installed along the gas flow direction is provided. On the downstream side of the thin tube structure 5, the diameter, cross-sectional shape, bend, etc. of the exhaust pipe can be freely selected.

FIG. 4 is a perspective view showing a schematic structure of a second embodiment of a single-wafer type vapor phase growth apparatus to which an exhaust pipe according to claim 4 is attached. This exhaust pipe is applied when there is no choice but to change the gas flow direction or the cross-sectional area or cross-sectional shape of the exhaust pipe due to the structure and layout of the single-wafer vapor phase growth apparatus. For example, if the place where the reaction vessel is installed is very close to the pump, or if the exhaust pipe connected to the reaction vessel must be bent immediately up, down, left, or right, the installation space for the vapor phase growth apparatus is limited. This is the structure applied in some cases. Inside the exhaust pipe 6 between the first straight line portion 6a of the exhaust pipe 6 and the second straight line portion 6c through the first bent portion 6b, a thin pipe made up of a plurality of thin pipes along the shape of the exhaust pipe 6 is formed. A structure 7 is provided. Capillary structure 7
The exhaust pipe after the end of the exhaust pipe, that is, on the downstream side of the second straight portion 6c, has the same diameter, cross-sectional shape, and exhaust pipe shape as in the case of FIG.
It is possible to freely select bends and the like.

Although the exhaust pipe of claim 5 is not shown, adapters are attached to both ends of the thin pipe structure provided in the exhaust pipe of claim 4 shown in FIGS. 3 and 4 to form a cartridge system. It is easy to replace the structural part.

Next, the quality test results of the epitaxial thin film obtained by using the single-wafer type vapor phase growth apparatus to which the exhaust pipe of this embodiment is attached will be described. The cross-sectional shape of the exhaust pipe is the same as the cross-sectional shape of the reaction vessel, and the exhaust pipe length is sufficiently long (exhaust pipe length is 3 m). The single-wafer vapor phase growth apparatus of FIG. 2 has a thin tube structure inside the exhaust pipe. Using the single-wafer vapor phase growth apparatus of FIG. 3 and the single-wafer vapor phase growth apparatus of FIG. 4 with a thin tube structure inside the vent portion of the exhaust pipe, an atmospheric pressure epitaxial growth of p-type 8-inch silicon wafer was tried. It was Trichlorosilane (non-doped) was selected as the source gas, a lamp was selected as the heating means, the same gas inlet and quartz glass reaction vessel were used, and only the exhaust pipe was sequentially replaced. As a result, no matter which exhaust pipe was used, the specific resistance and film thickness distribution of the obtained silicon epitaxial thin film were 3.3% and 1.4%, respectively, and reproducibility was high.

Similarly, atmospheric pressure epitaxial growth of a p-type 8-inch silicon wafer was tried using the single wafer type vapor phase growth apparatus shown in FIGS. Monosilane with slight doping was selected as the source gas, a lamp was selected as the heating means, the same gas inlet and quartz glass reaction vessel were used, and only the exhaust pipe was sequentially replaced. In order to prevent the amorphous silicon generated by the thermal decomposition of monosilane from adhering to the inner wall of the quartz glass reaction vessel interposed between the silicon wafer and the lamp, Japanese Patent Application No.
The gas was flowed according to the epitaxial growth apparatus and the epitaxial growth method shown in 249796.
As a result, no matter which exhaust pipe was used, the specific resistance and film thickness distribution of the obtained silicon epitaxial thin film were 4.2% and 2.3%, respectively, and reproducibility was high.

[0014]

As described above, according to the present invention, an exhaust pipe having a shape elongated in the same direction as a gas flow passing over a substrate set in a reaction vessel, preferably a cross-sectional area or a cross section. An exhaust pipe having the same cross-sectional area and cross-sectional shape as that of the reaction vessel is connected to the reaction vessel, and a thin tube structure is additionally provided in such an exhaust tube to have a rectifying function for gas passing over the substrate. Since it is decided that the gas is allowed to be discharged, it can be discharged to the outside of the system without disturbing the gas flow in the reaction vessel. This makes it possible to perform vapor phase growth with a good specific resistance and film thickness distribution, and to obtain a high quality epitaxial thin film. Further, when a thin tube structure is provided in the exhaust pipe, the gas flowing over the substrate can be discharged to the outside of the system without disturbing it even under reduced pressure, so that it can be applied to high-quality MOS epitaxial growth.

The thin tube structure can be attached to the bent portion of the exhaust pipe, and the vapor phase growth apparatus can be compactly assembled, which contributes to space saving of the apparatus. Further, according to the present invention, the gas flow can be easily and dynamically changed only by the gas inlet portion on the upstream side of the reaction vessel, and the setup time of the vapor phase growth apparatus can be significantly shortened. .

[Brief description of drawings]

FIG. 1 is a perspective view of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claims 1 and 2 is attached.

FIG. 2 is a perspective view of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claim 3 is attached.

FIG. 3 is a perspective view of a first embodiment of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claim 4 is attached.

FIG. 4 is a perspective view of a second embodiment of a single-wafer vapor phase growth apparatus to which an exhaust pipe according to claim 4 is attached.

FIG. 5 is a perspective view showing an example of a conventional single-wafer vapor phase growth apparatus.

FIG. 6 is a perspective view showing another example of a conventional single-wafer vapor phase growth apparatus.

[Explanation of symbols]

 1 Reaction container 2 Substrate 3,4,6,8 Exhaust pipe 5,7 Capillary structure

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiko Hino 1200 Manda, Hiratsuka-shi, Kanagawa Komatsu Seisakusho Laboratory (72) Inventor Naoto Hisanaga 1200, Hiratsuka-shi, Kanagawa Komatsu Seisakusho Co., Ltd.

Claims (5)

[Claims] 1. A single-wafer vapor phase growth apparatus having a long shape in the same direction as a gas flow passing over a substrate set in a reaction vessel of the single-wafer vapor phase growth apparatus. Exhaust pipe. 2. The exhaust pipe of the single-wafer vapor phase growth apparatus according to claim 1, wherein the cross-sectional area of the exhaust pipe is equal to the cross-sectional area of the reaction vessel. 3. The exhaust pipe of the single-wafer vapor phase growth apparatus according to claim 1, wherein the exhaust pipe has the same cross-sectional shape as that of the reaction vessel. 4. The exhaust pipe of the single-wafer vapor phase growth apparatus according to claim 1, wherein the exhaust pipe has a thin tube structure along a gas flow direction. 5. The exhaust pipe of the single-wafer vapor phase growth apparatus according to claim 4, wherein the thin tube structure is removable.