JPS626335B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for liquid phase epitaxial growth. Liquid phase epitaxial growth is an important technique for semiconductor devices using - group compound semiconductors, such as light emitting diodes and solar cells. However, although semiconductor devices using − group compound semiconductors have excellent characteristics, they are not yet widely used. This is due not only to the high cost of materials but also to the rise in manufacturing costs due to the low mass productivity of liquid phase epitaxial growth.

An example of a conventional liquid phase epitaxial growth apparatus is shown in FIGS. 1 to 3. This device is divided into upper, middle, and lower chambers 2, 3, and 4. By operating a slider 6, the saturated Ga melt 8 in the upper chamber 2 is passed through the hole 11 to the substrate in the middle chamber 3. The growth substrate 9 is placed in the holding device 10 and liquid phase epitaxial growth is performed on the growth substrate 9. After finishing, operate slider 6 again,
The slider 7 is moved by the engaging part 13 and stored in the chest-type drawer 5 of the lower chamber 4 through the hole 12.
In addition, in the figure, 1 is the main body of the apparatus.

With such equipment, the mass productivity of liquid phase epitaxial growth has improved, but saturation occurs during the first operation.
Since the Ga melt 8 is located in the upper chamber 2, the center of gravity is high and unstable, requiring skill to operate. Also, 3-tier room 2
Since the board 9 is divided into four parts, the size of the board 9 that can be used is limited. Furthermore, considering the lengths of the sliders 6 and 7, the length of the substrate 9 to be subjected to liquid phase epitaxial growth is
There is a limit to the number of sheets.

The present invention has been made in view of these points, and provides a liquid phase epitaxial growth apparatus that does not require skill in operation and can produce a large number of epitaxial wafers with a large area and good surface condition. It is.

Hereinafter, one embodiment of the present invention will be described in detail using FIGS. 4 and 5.

In the figure, 21 is the device main body, 25 is the board 26
It is a holding device that accommodates and holds the body 21, and is designed to be supported by being fitted into the main body 21. Note that the board 26 is fixed with a sliding plate 27 so that it does not move. Saturated Ga melt 2 composed of box 30
In the melt storage chamber 22 for storing 4, there is a saturated
An L-shaped slider 23 is provided for moving the Ga melt 24.

Liquid phase epitaxial growth for GaAs solar cells using the apparatus of the above embodiment will be described.

An L-shaped slider 2 is placed in a chamber 22 containing a saturated Ga melt 24 consisting of Ga melt, GaAs, Al, and Zn.
3 and a saturated Ga melt 24 are housed therein and installed in the main body 21. The amount of saturated Ga melt 24 stored in chamber 22 needs to be larger than the volume of substrate holding device 25 .

Next, the substrate 26 is installed on the substrate holding device 25,
The board 26 is fixed with a plate 27 so that it does not move, and then installed on the main body 21.

To perform epitaxial growth, the main body 21, which has been prepared as described above, is placed in a growth furnace. When the device reaches equilibrium at a predetermined temperature, the L-shaped slider 23 is slid in the direction of the arrow in FIG. Then, the saturated gas stored in chamber 22
The Ga melt 24 also moves in the direction of the arrow, and the L-shaped slider 23 closes the melt discharge port 28 provided on the bottom surface of the substrate holding device 25. The saturated Ga melt 24, which has filled the volume of the chamber 22, breaks the dirty film on the surface and the clean solution enters the substrate holder 25 from the melt inlet 29 provided on the side of the substrate holder 25. Get into it. Since the amount of the saturated Ga melt 24 is larger than the volume of the substrate holding device 25, clean films and the like remain in the chamber 22.

In this state, the growth furnace is slowly cooled and epitaxial growth is performed. Since this state exists during epitaxial growth, the composition ratio of the melt does not change. When the temperature drops to a predetermined temperature, slide the L-shaped slider 23 in the direction opposite to the arrow in FIG. Store it in.

In this way, since the inside of the substrate holding device 25 is filled only with the clean saturated Ga melt 24, an epitaxial wafer with a mirror-like, glossy surface can be obtained. Furthermore, since the saturated Ga melt 24 is located below the device, the device is stable and requires no skill to operate.

In addition, with this type of structured equipment, the substrates can be installed vertically in two stages, top and bottom, so many large substrates can be grown at once, and the distance the slider moves is short, making the equipment larger. . Furthermore, when installing the substrates in the apparatus, if they are held back to back, only one side will grow, and the number of substrates to grow will also increase.

Although the above embodiment describes liquid phase epitaxial growth of GaAlAs, it is possible to epitaxially grow other - group compound semiconductors by changing the melt and substrate materials.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of a conventional liquid phase growth apparatus, Fig. 2 is a side view thereof, and Fig. 3 is the same as Fig. 1.
4 is a vertical sectional view showing an embodiment of the present invention, and FIG. 5 is a sectional view taken along the line -- in FIG. 4. In the figure, 22 is a melt storage chamber, 23 is a slider, 24 is an epitaxial growth melt, 25 is a substrate holding device, 26 is a growth substrate, 28 is a melt outlet,
29 is a melt inlet. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Claims] 1. A melt storage chamber in which an epitaxial growth melt is stored, which has a melt discharge port on the bottom surface and a melt inlet port on the side surface, and is disposed above the melt storage chamber, and in which the growth substrate is stored. a substrate holding device that is movable within the melt storage chamber, closes the melt discharge port when moved in one direction, and allows the melt to flow into the substrate holding device from the melt introduction port; The liquid phase growth method is equipped with a slider that operates in such a manner that when the slider moves in the other direction, the melt discharge port opens and the melt that has flowed into the substrate holding device is discharged into the melt storage chamber. Device.