JPS63192228A - Device for forming semiconductor thin-film - Google Patents

Abstract

PURPOSE:To keep the constant surface temperature of a wafer at all times, and to obtain a growth layer having small temperature distribution in a wafer surface in various characteristics of the growth layer by inserting a cylinder, which consists of a conductive material and thickness of which extends over the skin depth or less of high frequency for high-frequency heating, between a wafer susceptor and a reaction pipe. CONSTITUTION:A cylinder 7, which is composed of a conductive material and thickness of which extends over the skin depth or less of high frequency, is inserted between a wafer susceptor 4 and a reaction pipe 2. The conductive cylinder 7 is induction-heated by high frequency, a wafer 5 is heated from the surface by radiant heat while the reaching of high frequency to the wafer susceptor 4 is not prevented because thickness extends over skin depth or less, and the wafer 5 is heated even by thermal conduction from the induction-heated wafer susceptor 4. Accordingly, the reproducibility of the temperature of the surface of the wafer is improved, and temperature distribution in a wafer surface is reduced, thus easily controlling the growth rate of a thin-film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor Fp film forming apparatus using an organometallic thermal decomposition method.

[Conventional technology]

FIG. 3 is a schematic cross-sectional view showing a conventional semiconductor thin film forming apparatus using an organometallic thermal decomposition method.

In this figure, 1 is a gas inlet for introducing the material gas, 2 is a reaction tube for confining the material gas, 3 is a gas outlet for guiding the reacted gas to the outside, and 4 is for holding the wafer. and a wafer susceptor for heating, 5 is a wafer placed on the wafer susceptor 4, and 6 is a high frequency coil for heating the wafer susceptor 4 with high frequency.

Next, the operation will be explained using the case of growing a GaAs thin film as an example. In this case, (CH3)1Ga and Ast(3) are generally used as the material gases.

When a high frequency is applied to the high frequency coil 6, the wafer susceptor 4 is heated by induction, and the heat is conducted to the wafer 5 to lower the temperature on the surface of the wafer 5. The raw material gas introduced into the reaction tube 2 through the gas inlet 1 causes a reaction according to the following equation (1) on the surface of the heated wafer 5.

(CH3)5Ga+AsH, →GaAs+4 Cl-1
4-(ll) GaAs generated by this reaction is deposited on the wafer 5. If the wafer 5 has a lattice constant equal to or almost equal to GaAs such as GaAs, epitaxial growth occurs. Equation (1) C H4, ungenerated gas, intermediate products, carrier gas, etc. generated by the reaction are discharged to the outside of the reaction tube 2 through the gas outlet 3.The thickness and carrier concentration of the GaAs layer deposited on the wafer 5 These characteristics depend on the temperature of the surface of the wafer 5.

[Problem that the invention seeks to solve]

Since the conventional semiconductor thin film forming apparatus is configured as described above, as the growth continues, GaAs, As, etc. adhere to the wafer susceptor 4, and as a result, the adhesion between the wafer 5 and the wafer susceptor 4 deteriorates. There have been problems in that the growth rate and the like are difficult to control because the temperature on the surface of the wafer 5 changes.

Further, if the wafer 5 is too large with respect to the wafer susceptor 4, there is a problem that the growth layer has variations within the plane of the wafer 5.

This invention was made to solve the above-mentioned problems, and it maintains a constant wafer surface temperature regardless of the adhesion between the wafer and wafer susceptor, and also maintains the characteristics of the growth layer within the wafer surface. An object of the present invention is to obtain a semiconductor Y4 film forming apparatus capable of obtaining a growth layer with a small temperature distribution.

[Means for solving problems]

In the semiconductor thin film forming apparatus according to the present invention, a cylinder made of a conductive material and having a thickness equal to or less than the skin depth of a high frequency for high frequency heating is inserted between a wafer susceptor and a reaction tube.

[Effect]

The conductive cylinder in this invention is induction heated by high frequency waves, and the radiant heat heats the wafer from the surface, and since its thickness is less than the skin depth, the high frequency waves cannot be prevented from reaching the wafer susceptor, and the wafer is heated by induction. The wafer is heated by conduction from the heated wafer susceptor.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of the vicinity of a reaction tube showing an embodiment of the present invention. In this figure, the same reference numerals as in FIG. 3 indicate the same parts, and 7 is a cylinder made of a conductive material, for example carbon.

Further, FIG. 2 is a partially cutaway perspective view showing the positional relationship among the wafer susceptor 4, wafer 5, and carbon cylinder 7 in an easy-to-understand manner.

Next, the operation will be explained. The growth mechanism is the same as the conventional one, so it will be omitted.

When a high frequency is applied to the high frequency coil 6, the cylinder 7 is heated by induction. In addition, the thickness of the cylinder 7 is less than the high frequency skin depth, for example, when using a frequency of 400 KHz,
Since its thickness is designed to be 2III11 or less, the high frequency also reaches the wafer susceptor 4, and the wafer susceptor 4
It is also heated by induction.

The wafer 5 placed on the wafer susceptor 4 is heated by thermal conduction from the wafer susceptor 4 and by thermal radiation from the cylinder 7. In particular, the wafer 5 is heated mainly by the cylinder 7.
Heated by thermal radiation from. Therefore, wafer 5
Even if the adhesion of the wafer susceptor 4 deteriorates, the surface temperature of the wafer 5 is kept almost constant. Further, inside the circle vJ7, the temperature is constant in the cylindrical direction due to symmetry, so the temperature distribution within the surface of the wafer 5 can be made small.

In addition, in the above embodiment, the wafer susceptor 4 and the circle r:
Although 47 is made of carbon, it goes without saying that other conductive materials may be used.

〔Effect of the invention〕

As explained above, in this invention, a cylinder made of a conductive material and having a thickness less than the high frequency skin depth is inserted between the wafer susceptor and the reaction tube, which improves the reproducibility of the temperature on the surface of the sea urchin. Furthermore, since the temperature distribution within the wafer surface becomes smaller, there is an effect that the growth rate of the thin film can be easily controlled.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a semiconductor thin film forming apparatus showing an embodiment of the present invention, FIG. 2 is a perspective view showing the arrangement relationship between a wafer susceptor, a wafer, and a cylinder of the present invention, and FIG. 3 is a conventional semiconductor thin film forming apparatus. FIG. 2 is a schematic cross-sectional view of the device. In the figure, 2 is a reaction tube, 4 is a wafer susceptor made of a conductive material, 5 is a wafer, 6 is a high frequency coil, and 7 is a cylinder made of a conductive material. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 7, Cylinder Figure 2 Figure 3 Procedural amendment (voluntary) 6332a Showa year, month, day, Commissioner of the Japan Patent Office
1. Indication of the incident Patent Application No. 1982-23951 2
, Title of the invention Semiconductor thin film forming apparatus 3, Representative of the person making the amendment Moriya Shiki 4, Agent □--9 (63,3.251 5, Claims column of the specification to be amended and the claims of the invention Detailed Explanation Column 6, Contents of Amendment (1) The claims of the specification are amended as shown in the attached sheet. (2) "Reduce the temperature" on page 2, line 15 of the specification is changed to "
Raise the temperature. ” he corrected. (3) Similarly, on page 4, line 16, "by heat conduction" is amended to "also by heat conduction." (4) Similarly, the "cylindrical direction" on page 6, line 2 is corrected to "circumferential direction of the cylinder." Above 2, Claims (1) ``A process in which a wafer fixed on a wafer susceptor is removed by a high-frequency heating method using an organic metal thermal decomposition method'' and a raw material gas is introduced into a reaction tube. A semiconductor thin film forming apparatus for forming a thin film on a semiconductor, characterized in that a cylinder made of a conductive material and having a thickness equal to or less than the skin depth of a high frequency is inserted between the wafer susceptor and the reaction tube. Thin film forming equipment. (2) The semiconductor thin film forming apparatus according to claim 1, wherein the conductive cylinder is made of carbon.

Claims (2)

[Claims] (1) In a semiconductor thin film forming apparatus that uses an organic metal pyrolysis method to heat a wafer fixed on a wafer susceptor by high-frequency heating by introducing a raw material gas into a reaction tube to form a thin film on the wafer. . A semiconductor thin film forming apparatus, characterized in that a cylinder made of a conductive material and having a thickness equal to or less than the skin depth of a high frequency is inserted between the wafer susceptor and the reaction tube. (2) The semiconductor thin film forming apparatus according to claim (1), wherein the conductive cylinder is made of carbon.