JPH0523583Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for liquid phase epitaxial growth of semiconductor crystals, and particularly to an apparatus for epitaxially growing semiconductor crystals by a temperature difference method.

[Conventional technology and problems]

Conventionally, in a liquid phase epitaxial growth apparatus for semiconductor crystals, a substrate crystal placed on a slider that is linearly moved in one direction is brought into contact with at least one solution (melt) in which a growth material is dissolved. By holding the substrate for a certain period of time, a semiconductor crystal is epitaxially grown on the substrate crystal. In this case, for example, as shown in FIG. 3, a carbon jig 2 placed inside a quartz tube 1 of a heating furnace is used. This jig 2 has at least one melt tank 2a that receives a melt 3 in which a growth material, that is, a melt material, a semiconductor material, and an impurity material is dissolved. A slider 4 carrying substrate crystals (not shown) on which the melting process is to be performed is brought into contact with the slider 4, and these substrate crystals are sequentially moved in one direction so as to face each melt tank 2a.

By the way, in the upper part of each melt tank 2a, there is provided a charging hole 2b for putting the above-mentioned growth material into each melt tank 2a, and each charging hole 2b is designed to prevent dust etc. from entering during crystal growth. It is closed by a carbon cap 5 (see Fig. 4).
This cap 5 is fitted against the input hole 2b, and the fit is approximately 10 μm.

However, when the jig 2 described above is set in the quartz tube 1 of a heating furnace and the inside of the quartz tube 1 is evacuated, each cap 5 is rubbed against the charging hole 2b of each melt tank 2a. Because of this, the cap 5 may sometimes pop out or come off from the insertion hole 2b. This is because the pressure inside the quartz tube 1 becomes lower than the pressure inside the melt tank 2a when it is evacuated, and since the cap 5 is ground against the input hole 2b, the air inside the melt tank 2a is This is to push up the cap 5 when passing into the quartz tube 1.

[Purpose of invention]

In view of the above points, the present invention is designed to prevent the cap fitted into the melt tank's charging hole from popping out or coming off when the melt tank is set in the quartz tube of a heating furnace and the inside of the quartz tube is evacuated. An object of the present invention is to provide a liquid phase epitaxial growth apparatus for semiconductor crystals.

[Means and actions for solving problems]

According to the present invention, the above object is achieved by bringing the substrate crystal into contact with at least one melt containing the growth material received in the melt tank and holding it for a certain period of time to form a semiconductor on the substrate crystal. In a semiconductor liquid phase epitaxial growth apparatus for epitaxially growing crystals, a recess is formed on the inner circumferential surface of a charging hole provided at the top of a melt tank and on the outer circumferential surface of a cap fitted into this charging hole. This is achieved by forming a section, so that when the cap is lifted a predetermined small distance relative to the input hole of the melt tank, the two recessed sections communicate with each other.

Preferably, both of the recesses are in the shape of a groove, or the recess of the charging hole of the melt tank is in the shape of a groove, and the recess of the cap is a flat notch.

According to this invention, when a melt tank is set in a quartz tube of a heating furnace and the inside of the quartz tube is evacuated, the pressure inside the quartz tube gradually decreases to be lower than the pressure inside the melt tank. When the cap is pushed up by this pressure difference, the cap is pushed up by a small predetermined distance, and the recess formed on the inner circumferential surface of the charging hole of the melt tank and the recess formed on the outer circumferential surface of the cap are separated. are in communication with each other, and the air in the melt tank escapes into the quartz tube through these recesses, so the pressure in the melt tank becomes almost the same as the pressure in the quartz tube, and the cap naturally closes. When the cap is lowered and completely inserted into the charging hole, the cap will not pop out or come off due to the pressure difference mentioned above.Thus, when the vacuum inside the quartz tube is finished, the pressure inside the melt tank will be reduced. Since the pressure is almost the same as the pressure inside the quartz tube, the cap completely fits into the input hole of the melt tank during crystal growth, and at this time, since the two concave portions are not in communication with each other, the cap is completely inserted into the melt in the melt tank. There is no risk of dust etc. getting in there.

〔Example〕

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows the vicinity of the injection hole of the melt tank of an embodiment of the liquid phase epitaxial growth apparatus according to the present invention. An input hole 11 is provided for introducing growth materials such as impurity materials, and a carbon cap 12 is fitted into this input hole 11 to prevent dust from entering the melt tank 10 during crystal growth. has been done. The cap 12 is fitted with the charging hole 11 of the melt tank 10, and a flange 12a provided around the upper edge of the cap 12 allows the cap 12 to fit into the charging hole 11.
It is adapted to be locked to the upper edge of 1.

The above configuration is similar to that of a conventional liquid phase epitaxial growth apparatus.

In the apparatus according to the present invention, a groove 13 is further provided on the inner peripheral surface of the charging hole 11 of the melt tank 10, and a groove 14 is provided on the outer peripheral surface of the cap 12. The groove portion 13 of the melt tank 10 is cut out in the inner circumferential surface of the input hole 11 of the melt tank 10 and extends vertically from an upper region thereof, that is, a position slightly above the longitudinal center to an upper edge. Further, the groove portion 14 of the cap 12 is similarly cut out in the outer circumferential surface of the cap 12, extending vertically from a lower region thereof, that is, a position slightly below the longitudinal center to a lower edge. Each groove 1 formed in this way
3 and 14 are positioned so as to be vertically aligned with each other when the cap 12 is inserted into the insertion hole 11.

The embodiment of the growth apparatus according to the present invention is constructed as described above, and the melt tank 10 is set in, for example, a quartz tube of a heating furnace as shown in FIG.
When the inside of this quartz tube is evacuated, when the pressure inside the quartz tube gradually decreases and becomes lower than the pressure inside the melt tank 10, the air inside the melt tank 10 pushes up the cap 12 due to the pressure difference. 12 is pushed up by a predetermined small distance (the distance indicated by the symbol d in FIG. 1B), the groove 1 provided on the inner peripheral surface of the charging hole 11 of the melt tank
3 is a groove 1 provided on the outer peripheral surface of the cap 12;
Since it will communicate with melt tank 1
The air inside the melt tank 10 escapes through the grooves 14 and 13 into the quartz tube, that is, to the outside of the melt tank 10.

As a result, the pressure inside the melt tank 10 becomes almost the same as the pressure inside the quartz tube, and there is no pressure difference, so
The cap 12 descends due to its own weight and completely fits into the charging hole 11 as shown. As the evacuation progresses further, by repeating the above operations, air is removed before the pressure difference between the pressure inside the melt tank 10 and the pressure inside the quartz tube becomes too large. Therefore, the cap 12 will not pop out or come off from the insertion hole 11.

Thus, when the vacuum inside the quartz tube is finished, the pressure inside the melt tank 10 is almost the same as the pressure inside the quartz tube, and therefore, during crystal growth, the pressure inside the melt tank 10 is almost the same as the pressure inside the quartz tube.
is held in a state where it is completely fitted into the charging hole 11 of the melt tank 10 as shown in the figure due to its own weight.

FIG. 2 shows another embodiment, in which cap 1
The structure is the same as that of the embodiment shown in FIG. 1, except that the outer circumferential surface of the second embodiment 2 is provided with a flat notch 14' instead of the groove 14, and its operation is also the same. Furthermore, since the flat notch 14' provided in the cap 12 has a certain width in the circumferential direction, when the cap 12 is inserted into the charging hole 11, the alignment range with respect to the charging hole 11 is wide. 12 with respect to the input hole 11 is not required.

In the above-described embodiment, the vertical length of the groove 13 and the groove 14 or the notch 14' is set to slightly forward of the vertical center from the upper edge or the lower edge, respectively. Alternatively, it is clear that a similar effect can be obtained by vertically shifting the lower or upper ends of the notches 14' so that they are arranged at a slight distance from each other in the vertical direction.

[Effect of idea]

As described above, according to the present invention, the substrate crystal is brought into contact with at least one melt containing the growth material received in the melt tank and held for a certain period of time, so that the growth material is melted onto the substrate crystal. In a semiconductor liquid phase epitaxial growth apparatus for epitaxially growing a semiconductor crystal, on the inner peripheral surface of a charging hole provided in the upper part of a melt tank, and on the outer peripheral surface of a cap fitted into the charging hole, each recess is provided, and the liquid phase epitaxy of the semiconductor crystal is arranged such that the recesses communicate with each other when the cap is lifted a predetermined small distance relative to the input hole of the melt bath. More preferably, both of the recesses are in the shape of a groove, or the recess of the input hole of the melt tank is in the shape of a groove, and the recess of the cap is a flat notch. When a melt tank is set in a quartz tube of a heating furnace and the inside of the quartz tube is evacuated, if the pressure inside the quartz tube gradually decreases and becomes lower than the pressure inside the melt tank, this pressure The cap is pushed up due to the difference, but when it is pushed up by a small predetermined distance, the recessed part provided on the inner circumferential surface of the charging hole of the melt tank and the recessed part provided on the outer circumferential surface of the cap communicate with each other. It happens.

Therefore, the air in the melt tank escapes into the quartz tube through these recesses, so the pressure in the melt tank becomes almost the same as the pressure in the quartz tube, and the cap naturally lowers to completely meet the input hole. Once inserted, the cap will not pop out or come off due to the pressure difference mentioned above, and thus, when the vacuum inside the quartz tube is finished, the pressure inside the melt tank will be approximately the same as the pressure inside the quartz tube. Therefore, during crystal growth, the cap completely fits into the input hole of the melt tank, and since the recessed portions do not communicate with each other at this time, there is no possibility that dirt or the like will enter the melt in the melt tank.

[Brief explanation of the drawing]

FIG. 1 shows the vicinity of the melt tank charging hole of an embodiment of the liquid phase epitaxial growth apparatus according to the present invention, in which A is a plan view, B is a schematic sectional view, and C is a perspective view of the cap. FIG. 2 is a diagram similar to FIG. 1 of another embodiment of the present invention. FIG. 3 is a schematic longitudinal cross-sectional view showing an example of a conventional liquid phase epitaxial growth apparatus, and FIG. 4 is a schematic cross-sectional view of the vicinity of the melt tank input hole in the apparatus shown in FIG. 10... Melt tank, 11... Input hole, 12...
Cap, 13, 14... groove, 14'... notch.

Claims (1)

[Claims for Utility Model Registration] (1) By bringing a substrate crystal into contact with at least one melt containing a growth material received in a melt tank and holding it for a certain period of time,
In a semiconductor liquid-phase epitaxial growth apparatus for epitaxially growing a semiconductor crystal on a substrate crystal, the inner circumferential surface of the charging hole provided at the upper part of the melt tank, and the melt tank fitted into the charging hole of the melt tank The outer peripheral surface of the cap is provided with recessed portions, and the recessed portions communicate with each other when the cap is lifted a predetermined small distance with respect to the insertion hole. A device for liquid phase epitaxial growth of semiconductor crystals. (2) Claim 1 of the utility model registration claim, characterized in that each of the recesses provided on the inner circumferential surface of the charging hole of the melt tank and the outer circumferential surface of the cap is in the shape of a groove. equipment. (3) The recessed portion provided on the inner peripheral surface of the input hole of the melt tank is in the shape of a groove, and the recessed portion provided on the outer peripheral surface of the cap is a flat notch. Scope of claim for utility model registration No. 1
Equipment described in Section.