JP2830629B2 - Vapor phase growth equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth apparatus for growing a crystal of a growth layer of a semiconductor or a compound on a substrate.

[0002]

2. Description of the Related Art A vapor phase growth apparatus is widely used for growing a semiconductor or a superconducting oxide thin film on a substrate.
Among them, metal organic chemical vapor deposition apparatuses suitable for growing compound semiconductors are widely used, and many compounds are grown. Conventional vapor phase growth devices include, for example, the Journal of Cryst
al Growth) 69, 1984, pp. 10-14. FIG. 2 is a schematic configuration diagram of an example of a conventional vapor phase growth apparatus using a high-frequency coil as one of the local heaters. A plurality of types of growth gas supplied from the gas flow control device 21 are independently transported by a plurality of pipes 22,
It is sent to the reaction tube 23. Susceptor 2 in reaction tube 23
A substrate 25 is disposed on 4, and a high-frequency coil 26 is disposed around the reaction tube 23 for heating the substrate.

[0003]

It is noted that GaAs, a III-V compound semiconductor, and ZnSe, a II-VI compound semiconductor, have substantially the same lattice constant and a significantly different band gap. Research has recently been undertaken. On the other hand, ZnSe has been attracting attention as a blue light emitting element material.
Since there is no e-substrate and the substrate is very expensive, the growth of ZnSe requires a relatively inexpensive G
aAs substrates are often used. However, FIG.
When, for example, a GaAs / ZnSe heterostructure film is to be grown by using a vapor phase growth apparatus using a high-frequency coil as shown in (1), a high quality heterointerface cannot be formed, and the film quality of the grown layer is not good. There was a problem. This is for the following reason.

In order to grow GaAs, for example, by a conventional vapor phase growth apparatus using a high-frequency coil, first, a growth material is supplied to a substrate. The supplied growth raw material is decomposed by the heat of the substrate or the susceptor, and the decomposition product adheres to the substrate, whereby the growth proceeds. However, decomposition products that did not contribute to the growth at this time adhere to the periphery of the susceptor and the inner wall of the reaction tube. Then, ZnS
When e is grown, a decomposition product attached during GaAs growth is taken into the ZnSe layer, causing a problem that the hetero interface and the ZnSe layer are contaminated. This means that for a III-V compound semiconductor, the II and VI elements are impurities that govern the conductivity type, and similarly, the III and V groups behave similarly to the II-VI compound semiconductor. This is because they are impurities. Further, in this vapor phase growth apparatus, since deposits accumulate in the reaction tube every time they grow, the deposit often peels off from the tube wall of the reaction tube during the next growth and falls down onto the substrate. The grown layer obtained at this time had many crystal defects and was a problem.

On the other hand, in the conventional vapor phase growth apparatus, a vapor phase growth apparatus having an electric furnace instead of local heating using a high-frequency coil is also known. However, when an attempt is made to grow a GaAs / ZnSe heterostructure film using this apparatus, there is a problem that the growth material is adhered to the inner wall of the reaction tube near the area where the growth materials are mixed, and the growth is hindered.
It is not suitable for growing II-VI group compound semiconductors represented by nSe. Further, as an apparatus for growing a heterostructure film, two reaction tubes are provided, the two chambers are connected to each other, and the substrate is moved for each growth, so that the heterostructure film is vapor-phase grown. It is conceivable that the chamber is grown by the MBE method. However, in this case, there is a drawback that the operation is complicated because the substrate needs to be moved, and the apparatus becomes expensive. An object of the present invention is to solve such a conventional problem and to provide a vapor phase growth apparatus capable of growing a high-quality heterostructure film.

[0006]

According to the present invention, in order to achieve the above object, a substrate or a substrate supported on a susceptor is removably housed, and the substrate is contacted with a growth source gas while heating the substrate. In a vapor phase growth apparatus provided with a reaction tube for growing crystals on the substrate, an electric furnace disposed outside the reaction tube and covering the reaction tube, and a local heater disposed outside the reaction tube And a moving mechanism for movably supporting the electric furnace and the local heater, respectively, such that the moving mechanism of the local heater and the electric furnace does not impede the movement of one while moving the other. This constitutes a vapor-phase growth apparatus formed so as to be movable.

[0007]

Using the vapor phase growth apparatus of the present invention, for example, Ga
When performing continuous growth of As and ZnSe, the following is performed. Using diethyl gallium chloride ((C ₂ H ₅ ) ₂ GaCl) and AsH ₃ as GaAs growth raw materials, the substrate is heated by an electric furnace. In this method, as is well known, since the reaction tube itself is also heated in an electric furnace, adhesion to the reaction tube wall does not occur at all, and high-quality GaAs can be grown. Subsequently, the electric furnace is moved away from the substrate portion, and ZnSe is grown using a local heater for heating the substrate.
At this time, a normal metal organic chemical vapor deposition method may be used. G
Since the reaction tube and the susceptor are not contaminated at all during the growth of aAs, a heterostructure film having a favorable heterointerface and free from impurity contamination can be obtained. When the vapor phase growth apparatus of the present invention is used, the deposits deposited on the inner wall of the reaction tube and the susceptor after the growth is completed are easily removed by heating the reaction tube using an electric furnace and vapor phase etching with a halogen gas such as HCl. it can. As a result, the reaction tube can be kept in a normal state for each growth.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of one embodiment of the present invention. A substrate 17 supported on a susceptor 18 is accommodated in a reaction tube 13 of the vapor phase growth apparatus. A pipe 12 is provided in the reaction tube 13.
Is inserted, and the base end side of the pipe 12 is connected to a gas flow control device 11 for supplying a growth source gas into the reaction tube 13. The electric furnace 14 is provided so as to cover the outer periphery of the reaction tube 13. The electric furnace 14 is supported by rails 15a arranged along the axial direction of the reaction tube 13 and supported by an electric furnace moving mechanism (not shown) that engages with the rail 15a so as to be movable in the axial direction of the reaction tube 13. . As the electric furnace moving mechanism section, a feed screw, a nut member screwed to the electric furnace 14 and fixed to the electric furnace 14 side, a drive motor for the feed screw, and the like are applied as an example. The local heater 16 composed of an infrared radiation lamp or the like is arranged on the outside of the reaction tube 13 in the vicinity of the housing of the substrate 17. Local heater 16 is rail 15b
And is movably supported by a local heater moving mechanism (not shown). As the local heater moving mechanism, one having a structure substantially similar to the electric furnace moving mechanism is applied as an example. In addition, the electric heater 14 is connected to the reaction tube 13 by the electric furnace moving mechanism.
When moved to the local heater 16 side along the axial direction of
They are formed so that they do not interfere with each other. For example, interference can be prevented by arranging the rails 15a and 15b orthogonal to each other as shown in FIG.
With the above structure, the substrate 17 and the susceptor 18 are heated by the electric furnace 14 and the local heater 16 and come into contact with the growth source gas from the gas flow controller to grow crystals.

Next, a vapor phase growth method using the vapor phase growth apparatus configured as described above will be described. Gas flow control device 1
The plurality of growth source gases supplied from
2 to the reaction tube 13. An electric furnace 14 is installed so as to cover the reaction tube 13, and the electric furnace 14 can be moved in the axial direction of the reaction tube 13 by a rail 15 a. First, the electric furnace 14 is heated close to the substrate to vapor-grow the first compound semiconductor. continue,
The electric furnace 14 is moved away from the substrate, and
Is heated close to the substrate to vapor-grow the second compound semiconductor. This local heater 16 is constituted by an infrared lamp. The local heater 16 can be moved by the rail 15b so as not to hinder the movement of the electric furnace 14. FIG. 1 shows a susceptor 18 using a local heater 16.
Through which the substrate 17 is heated for growth. When growing using the electric furnace 14, the local heater 16 is kept away from the reaction tube 13, and the electric furnace 14 is
Is moved to the position where is heated.

In this embodiment, an infrared radiation lamp is used as the local heater. However, the present invention is not limited to this, and another heater such as a high-frequency induction heating means using parallel electrodes or a split electric furnace may be used. In this embodiment, rails were used for moving the electric furnace and the local heater, but it is obvious that the present invention is not limited to this.

[0011]

As described above, according to the present invention,
Even if a III-V group compound semiconductor and a II-VI group compound semiconductor are continuously grown, a heterostructure film having a high quality heterointerface can be grown. In addition, since the reaction tube can be vapor-phase etched each time it is grown, the reaction tube is always kept in a normal state,
A high quality grown film with few defects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vapor phase growth apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an example of a conventional vapor phase growth apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Gas flow controller 12 Pipe 13 Reaction tube 14 Electric furnace 15a, 15b Rail 16 Local heater 17 Substrate 18 Susceptor 21 Gas flow controller 22 Pipe 23 Reaction tube 24 Susceptor 25 Substrate 26 High frequency coil

Claims (1)

(57) [Claims] 1. A gas phase having a reaction tube for accommodating a substrate or a substrate supported on a susceptor and allowing the substrate to come into contact with a growth source gas while heating the substrate to grow crystals on the substrate. In the growth apparatus, an electric furnace disposed outside the reaction tube so as to cover the reaction tube, a local heater disposed outside the reaction tube, and a movement for movably supporting the electric furnace and the local heater, respectively. A vapor phase growth apparatus, comprising a mechanism, wherein the local heater and the moving mechanism of the electric furnace are formed so as to be movable so as not to hinder the movement of one of the electric heater and the electric furnace.