JPH05114565A - Slide boat member and liquid phase epitaxy using same - Google Patents

Abstract

PURPOSE:To bring a melt into even contact with a wafer for preventing the oxide etc., contained in the solution from adhering to the wafer thereby making both luminescence efficiency and luminescence wavelength characteristics uniform after the growth of an epitaxial film. CONSTITUTION:The melt 9 in a solution reservoir 5 is fed from the lower part of a wafer 4 in a growing chamber 2 through a flow path 3. Next, the glowing chamber 2 filled up with the melt 9 is temperature-controlled so that an epitaxial layer may be grown on the surface of the wafer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide boat member capable of easily adjusting a grown film thickness and suitable for growing a multi-layer structure, and a liquid phase epitaxial growth method using this member.

[0002]

2. Description of the Related Art Crystal growth in liquid phase epitaxy takes place in the state of thermal equilibrium which is the closest to that of various crystal growth methods. Therefore, the crystals obtained by liquid phase epitaxy are
Generally, it has a high degree of integrity with few structural defects. Since the liquid phase epitaxy is performed at a temperature much lower than the melting point of the semiconductor, the crystal obtained by the epitaxy, that is, the structure of the epitaxial layer is also highly complete. Therefore, the liquid phase epitaxial growth method is used to grow various epitaxial layers.

[0003] As the liquid phase epitaxial growth method, for example, as shown in FIG. 7, the growth chamber 10 by the piston 101
2 is injected with a solution for epitaxial growth (hereinafter also referred to as “melt”) 103, the melt 103 is brought into contact with the wafer 104, and the temperature is adjusted by a slow cooling method or a temperature difference method. There is also a method of growing a film. Also, FIG.
There is also a method of arranging the melt 203 above the growth chamber 202 and bringing the melt 203 into contact with the wafer 204 so as to carry out growth as shown in FIG.

[0004]

In the method using the piston shown in FIG. 7, the film thickness of the epi film can be easily adjusted by adjusting the melt injection rate. However, in the case of liquid phase epitaxy of a multi-layered epitaxial film, the structure of the device is complicated and the cost for automatic operation is high.

On the other hand, in the method of pouring the melt shown in FIG.
By providing an appropriate number of melt solution reservoirs, a multi-layer epi film can be grown in liquid phase. However, in this method, since the melt is poured directly onto the wafer surface, the melt is unevenly contacted with the wafer surface to cause abnormal growth locally, or oxides contained in the solution are not included in the wafer surface. Adheres to and hinders growth. Therefore, the light emission efficiency and the light emission wavelength characteristic on the surface of the wafer after growth become non-uniform, which causes inconvenience when used as a semiconductor device.

Therefore, as means for solving such a problem, for example, in Japanese Patent Publication No. 2-58769, a spacer is provided so that the raw material solution does not come into contact with the substrate during the fall, and the raw material solution is temporarily added to the spacer. After passing through the lower part, a method of injecting into the gap between the spacer and the substrate is disclosed. According to this method, the melt uniformly contacts the wafer surface, and the oxide or the like does not contact the wafer surface, so that uniform growth of the epi film can be expected. However, when a large number of epitaxial films are grown at the same time by this method, a large number of spacers are required, the structure of the apparatus becomes complicated, and the space in the growth chamber cannot be effectively used.

Therefore, the present invention is a slide boat member which can easily adjust the film thickness of the epi film and is suitable for growing a multi-layer structure. The structure is simple and the space in the growth chamber is effectively used. The object of the present invention is to develop a member that can be used and a liquid phase epitaxial growth method using this member.

[0008]

In order to achieve the above object, the present inventors have developed the following slide boat member and a liquid phase epitaxial growth method using this member.

That is, the slide boat member of the present invention is a slide boat member which slides under a member provided with a solution reservoir, and has a space (growth chamber) for growing an epitaxial layer on a wafer, At least a flow path communicating from the solution reservoir to a lower part of the wafer is provided, and a preferred embodiment thereof is characterized in that the flow path is provided at a side (side surface side) of the space (growth chamber). To do.

Further, the liquid phase epitaxial growth method of the present invention is a liquid phase epitaxial growth method using the slide boat member, wherein the solution for epitaxial growth in the solution reservoir is lower than the wafer through the flow path. And the growth solution is brought into contact with the wafer. In the present invention, the wafer means various substrates that may have an epi film.

In the present invention, the angle (θ) formed by the wafer and the horizontal line can take any value from 0 ° (horizontal) to 90 ° (vertical). However, in order to make the epitaxial layer grown on the wafer have a uniform thickness, θ is 45.
In the case of growing an epi film of less than or equal to 0 ° C, especially about 0.5 to 10 μm, about 30 to 45 ° is desirable, and 100 μm
When growing an epi film of about 10 to 30 °, it is desirable.

[0012]

The slide boat member of the present invention has a flow path from the upper epitaxial growth solution reservoir to the lower part of the wafer in the growth chamber. Therefore, according to the liquid phase epitaxial growth method of the present invention using the member, the melt in the solution reservoir is directly supplied to the lower portion of the wafer through the flow path by sliding the member or the member having the solution reservoir. To be done. That is, when the melt is supplied, the melt does not flow on the surface of the wafer, and the melt interface rises substantially horizontally from the lower part of the wafer, so that the melt uniformly contacts the wafer.
In addition, the oxides and the like contained in the solution are prevented from mixing into the growth chamber, and when the used melt flows out to the reservoir after the growth is completed, the oxides and the like directly flow out to the reservoir through the flow path.

[0013]

EXAMPLES Examples of the slide boat member of the present invention and a liquid phase epitaxial growth method using this member will be shown below.

[Slide Boat Member] As the slide boat member of the present invention, a member 1 of high purity carbon as shown in FIG. 1 is exemplified. In FIG. 1, 2 is a growth chamber, 3
Is a flow path, and 4 is a wafer. A member 6 having a solution reservoir 5 is arranged above the member 1, and a member 8 having a used solution reservoir 7 is arranged below the member 1 so as to slide with respect to the member 1. There is. In FIG. 1, the wafer 4 was set so as to be inclined by 15 ° with respect to the horizontal line.

In this embodiment, only the linear passage is provided as the flow path 3, but the flow path 3 is not limited to the curved shape.
The number of the flow paths 3 is also not limited. The sliding of each member 1, 6, 8 is not limited to one-dimensional (linear) sliding, and may be two-dimensional (planar) sliding.

Although only one wafer is shown in FIG. 1, it is possible to grow a large number of wafers at the same time, an example of which is shown in FIG. In FIG. 2, the slide boat member
10 has a plurality of stages (4 stages in FIG. 2), and each stage has 2 stages.
Each of the wafers 14 and 14 'can be arranged. Two
The wafers 14 and 14 'are arranged parallel to each other and their growth surfaces are opposed to each other.

In the present invention, the space can be saved by providing the flow path on the side of the growth chamber. Specifically, the modes shown in FIGS. 3 and 4 are exemplified. 3 is a cross-sectional view in the sliding direction, and FIG. 4 is a cross-sectional view in the width direction. In the present embodiment, the member 26 having the solution reservoir 25 has an inverted U-shaped cross section so as to cover the member 21 having the growth chamber 22 , so that the flow path 23 slides laterally of the growth chamber 22. It is provided in. In the figure, the melt 29 flows into the growth chamber 22 from below both ends in the width direction of the growth chamber 22 and contacts the wafer 24. After the growth is completed, the member 21 (or the member 28) is slid to pour the melt 29 into the used solution reservoir 27 .

In the above embodiment, the flow passage was provided in the member having the solution reservoir, but as shown in FIGS. 5 and 6, the flow passage 33 is provided on the side of the growth chamber 32 of the member 31. May be. Similar to the above embodiment, FIG. 5 is a sectional view in the sliding direction, and FIG. 6 is a sectional view in the width direction, and alternate long and short dash lines in the figure indicate cutting points of each other. In this embodiment, the member 36
By sliding (or the member 33), the solution reservoir 3
The melt 39 in 5 merges in the lower part of the growth chamber 32 through the flow paths 33 at both ends in the width direction, and contacts the wafer 34. After the growth is completed, the member 31 (or the member 38) is slid to pour the melt 39 into the used solution reservoir 37 , as in the above-described embodiment.

[Liquid phase epitaxial growth method]
An example of a liquid phase epitaxial growth method using the slide boat member 1 shown in FIG.

In the present invention, the material forming the wafer and the melt is not particularly limited, a desired material is used, and the growth conditions and the like can be appropriately determined. However, in order to make the present invention easier to understand, the growth method in the case where the wafer is a GaAs substrate and the melt is an Al-Ga-As solution will be described in detail below.

As the wafer, a (100) plane of a disk-shaped single crystal GaAs substrate 1 having a diameter of 50 mm is used. EPD of substrate
(Dislocation density) is 20,000 cm ^-2 or less, especially 5,0
00 cm ^-2 or less is desirable. The solution uses Ga as a solvent,
Single crystal GaAs and Al are used as solutes, and Si which is an amphoteric impurity is used as a dopant, and these solutes are dissolved in a Ga solvent. The ratio of each component in the solution is determined by the growth start temperature and the target emission wavelength.

First, GaAs cleaned by a known method
The (100) plane GaAs seed crystal substrate 1 is placed in a suitable growth chamber, for example, above or below the growth chamber 2 . still,
The composition of the melt 9 is adjusted so as to precipitate a solid solution having a desired composition at the growth start temperature, and the melt 9 is charged into the solution reservoir 5 . After that, high-purity hydrogen gas is caused to flow into the growth chamber 2 to sufficiently clean the atmosphere. Then, the temperature of the growth chamber 2 is raised to a temperature slightly higher than the equilibrium temperature of the melt 9, and the temperature of the growth chamber 2 is maintained for a certain period of time to homogenize the composition of the melt 9.

In this example, 1.7 mg of Al was added to 1 g of Ga in order to equilibrate the melt 9 at 935 ° C.
A solution charged with 120 mg of GaAs and 2.0 mg of Si was used. After heating the member 1 to 945 ° C. and homogenizing the composition of the melt 9 over 1 hour and 30 minutes, 935 ° C.
Cool down. After that, the member 1 is slid horizontally (to the right in FIG. 1) to allow the melt 9 to flow through the flow path 3 into the growth chamber.
Pour into 2 .

The growth chamber 2 is filled with the melt 9 to give 0.5 /
Cool to 600 ° C. at a cooling rate of minutes. After the growth is completed, while maintaining the temperature of the member 1 at 600 ° C., the member 1 is slid to the right so that the melt 9 flows into the used solution reservoir 7 . In order to facilitate the inflow of the melt, a passage may be provided to allow the air in the growth chamber 2 and the used solution reservoir 7 to escape to the outside.

The above growth program is only an example, and for example, in order to form an epitaxial growth layer having a multilayer structure, a member having a solution reservoir for the number of layers is used, and layers having different compositions and conductivity types are sequentially grown. You can do it. Further, by combining this method with the method of simultaneously growing a large number of wafers as described above, it is possible to manufacture an epitaxial growth layer having a multilayer structure at low cost.

[0026]

According to the slide boat member of the present invention,
The structure of the slide boat as a whole becomes simple, and the cost can be reduced even when the epitaxial film having a multilayer structure is grown by automatic operation. Further, according to the liquid phase epitaxial growth method using this member, the melt uniformly contacts the wafer and prevents the oxides and the like contained in the solution from adhering to the wafer, and the wafer surface after the epi film growth. The light emission efficiency and the light emission wavelength characteristic are uniform. Further, the melt inflow rate can be changed by adjusting the width of the flow path and the like. Therefore, by appropriately selecting the melt composition and the mixed crystal ratio of the substrate (including the substrate having the epitaxial film), a wide variety of semiconductor materials can be efficiently produced and applied to various applications. In addition, in the member of the present invention, the space can be saved by providing the flow channel on the side of the growth chamber.

[Brief description of drawings]

FIG. 1 is a sectional view in a sliding direction showing an embodiment of a member of the present invention.

FIG. 2 is a sectional view in the sliding direction showing a modified embodiment of the member of the present invention.

FIG. 3 is a sliding direction sectional view showing a modified embodiment of the member of the present invention.

FIG. 4 is a widthwise sectional view showing a modified embodiment of the member of the present invention.

FIG. 5 is a sliding direction sectional view showing a modified embodiment of the member of the present invention.

FIG. 6 is a widthwise sectional view showing a modified embodiment of the member of the present invention.

FIG. 7 is a cross-sectional view in a sliding direction showing a conventional liquid phase epitaxial growth method using a piston.

FIG. 8 is a sliding direction sectional view showing a liquid phase epitaxial growth method by a conventional slide boat method.

[Explanation of symbols]

1: Slide boat member 2 : Growth chamber 3: Flow path 4: Wafer 5 : Solution reservoir 9: Melt g: Gravity direction

Claims (4)

[Claims] 1. A slide boat member that slides under a member provided with a solution reservoir, and has a space for growing an epitaxial layer on a wafer and a flow path leading from the solution reservoir to a position below the wafer. A slide boat member having at least. 2. The slide boat member according to claim 1, wherein the flow path is lateral to the space. 3. A liquid phase epitaxial growth method using the slide boat member according to claim 1 or 2, wherein the epitaxial growth solution in the solution reservoir is supplied to a lower part of the wafer through the flow path. A liquid phase epitaxial growth method, which comprises contacting the wafer with the growth solution. 4. The growth method according to claim 3, wherein the wafer is tilted, and the tilt angle of the wafer with respect to the horizontal plane is 45 ° or less.