JPS628008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding liquid phase epitaxial growth apparatus.

The slide type liquid phase epitaxial growth equipment has
Various types have been proposed so far, but
In particular, semiconductors are grown by extruding and replacing the growth melt that has finished growing a certain layer with the next new growth melt, and using this melt to grow the next layer. Equipment that allows multiple epitaxial layers to be grown continuously on a substrate has good crystallinity and is designed to protect the epitaxial growth interface with the growth melt without exposing it to atmospheric gas. It is known as an apparatus that can obtain semiconductor elements with surface conditions.

FIG. 1 shows an example of such a conventional slide type liquid phase epitaxial growth apparatus. 1 is a base body in which liquid tanks 4 and 5 for storing different growth melts 2 and 3 are arranged side by side; 6 and 7;
8 is an extrusion piece positioned above the growth melts 2 and 3 in the liquid tanks 4 and 5, and has cam slopes 6a and 7a formed on one side of its upper surface, and 8 is slidably inserted into the upper part of the substrate 1. , cam slopes 6a, 7 by the tip cam surface 8a.
An operation slider capable of extruding the melts 2 and 3 through extrusion pieces 6 and 7 by pressing a, 9 a growth slider slidably in contact with the lower surface of the substrate 1, and 10 a growth slider. Two crystal substrates 11, 12
13 is a passage that communicates the growth chamber 12 with the liquid tank 4 or 5, and 14 is a passage that leads the drained liquid from the growth chamber 12 to the drained liquid tank 15.

Therefore, in the above configuration, the growth slider 9 is first positioned so that its passage 13 communicates with one of the liquid tanks 4 on the front side, and in this state, the operation slider 8 is moved to move the extrusion piece 6 downward. The growth melt 2 stored in the liquid tank 4 is pushed into the growth chamber 10 from this passage 13, thereby growing an epitaxial layer of, for example, GaAs on the crystal substrates 11 and 12. . Then, when the growth is completed by maintaining this state for a predetermined period of time, the growth slider 9 is further moved to open the passage 13 in the other liquid tank 5.
By moving the operation slider 8 again and pressing the extrusion piece 7 downward, the growth melt 3 in the liquid tank 5 and the previous melt 2 are drained from the passage 14. The crystal substrates 1 are pushed into the growth chamber 10 by being pushed into the liquid tank 15.
Continue to grow new epitaxial layers on the 1st and 12th sides. In other words, by sequentially performing the growth in this manner, a multilayer epitaxial layer can be obtained.

However, when observing the growth interface and surfaces of the crystal substrates 11 and 12 obtained by such a conventional slide type liquid phase epitaxial growth apparatus under a microscope, it is found that the substrate 12 placed on the top is placed on the bottom. The crystallinity and flatness are inferior to that of the placed substrate 11,
This had the disadvantage that it could not be used as an element requiring high quality crystals.

The reason for this is thought to be as follows. That is,
The solute elements melted in the growth melts 2 and 3 nucleate as the temperature of the growth furnace decreases, and precipitate in the melt and on the surface of the melt. Taking liquid phase epitaxial GaAs as an example, in the melt
GaAs has a lower specific gravity than the melt, in this case Ga, so it tries to float, but the depth of the melt is larger than the distance it rises (usually 5 to 10 mm), so it is found that it is mixed in the melt. Extrude this to pieces 6, 7
When extruded into the growth chamber 10 by the GaAs melts 2 and 3, because the height of the growth chamber 10 is low (usually about 1 mm), the GaAs precipitated in the melts 2 and 3 floats in the melt and reaches the upper crystal substrate 12. GaAs easily reaches and adheres to surfaces, and this deposited GaAs impairs the crystallinity and flatness of epitaxial interfaces and surfaces.

In order to improve these conventional drawbacks, this invention disposes a crystal substrate in the middle of the path to the growth chamber, and when the growth melt passes through, it removes deposited substances and removes the deposited substances. The supersaturated melt in the previous step is made to turn into a saturated melt.

An embodiment of the inventive device will be described in detail with reference to FIG. 2.

The embodiment shown in FIG. 2 is an enlarged perspective view of the passageway to the growth chamber in the apparatus configuration described above. In this FIG. 2, the same reference numerals as those in FIG. 17
In this case, they are spaced at intervals of approximately 300 μm.

Therefore, in the case of this embodiment, the operating slider 8 is moved and the extrusion pieces 6, 7 are used to open the liquid tanks 4, 5.
The growth melts 2 and 3 in the growth chamber 10 are transferred from the passage 13 to the growth chamber 10.
When the melt is pushed into the interior, the crystal substrate 17 captures and removes the precipitates mixed in the melt, and turns the supersaturated melt into a saturated melt, thereby removing unnecessary precipitates. In order to avoid adhesion of the melt onto the substrate 12, to avoid damaging the epitaxial interface, surface crystallinity, and flatness, and to guide the saturated melt to the growth chamber 10, the film thickness is controlled. The growth can be performed with good reproducibility.

In the above embodiment, a plurality of crystal substrates 17 are arranged in a comb-like shape, but it is also possible to make a large number of small holes in one crystal substrate and guide the melt through these small holes. Of course, the crystal substrate may be brought into contact with another crystal substrate and then introduced into the crystal chamber 10.

As detailed above, according to the present invention, when the growth melt is pushed into the growth chamber, the precipitates mixed in the melt are removed, so that the crystal substrate placed on top of the crystal substrate is removed. It is possible to uniformly grow an epitaxial layer with good crystallinity and flatness even for
Productivity is doubled as a result of being able to obtain two epitaxially grown crystals at the same time, the upper and lower layers, and since the supersaturated melt is adjusted to a saturated melt, there is no rapid rise in the temperature at the moment the melt contacts the crystal substrate. This method eliminates the need for growth, allows submicron-level film thickness control with good reproducibility, and has the advantage of being simple in structure and easy to implement.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional sliding type liquid phase epitaxial growth apparatus, and FIG. 2 is a cross sectional perspective view showing an enlarged main part of an embodiment of the sliding type liquid phase epitaxial growth apparatus according to the present invention. It is a diagram. 1... Substrate, 2, 3... Melt for growth, 4, 5...
...Liquid tank, 6,7...Extrusion piece, 8...Slider for operation, 9...Slider for growth, 10...Growth chamber,
11, 12...Crystal substrate for growth, 13...Passway, 15...Drainage tank, 16...Groove, 17...Crystal substrate for trapping precipitates.

Claims (1)

[Scope of Claims] 1. A base body in which a plurality of liquid tanks for storing a growth melt are formed side by side, an extrusion piece interposed in each of the liquid tanks, and an extrusion piece that is slidably held on the lower surface of the base body and has an internal structure. A growth slider provided with a growth chamber communicating with the liquid tank via a passageway and each of the extrusion pieces are sequentially pressed to supply the growth melt in the liquid tank from the passageway to the growth chamber at the corresponding position. In the configuration including an operation slider that is pushed out into a chamber, a crystal substrate for capturing precipitates to which a substance precipitated from the growth melt is attached is placed in the middle of the passage when pushed out from the liquid tank. 1. A slide type liquid phase epitaxial growth apparatus characterized in that the growth melt is disposed so that it passes through the passage while contacting the crystal substrate. 2. The sliding liquid phase epitaxial growth apparatus according to claim 1, wherein the crystal substrate for trapping precipitates is formed in a comb-teeth shape. 3. The sliding liquid phase epitaxial growth apparatus according to claim 1, wherein the crystal substrate for trapping precipitates is a perforated plate.