JPH0261137B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid phase growth apparatus for semiconductor crystals,
In particular, the present invention relates to an apparatus for growing semiconductor crystals using a temperature difference method.

[Conventional technology and problems]

Conventionally, when growing a semiconductor crystal such as a compound semiconductor, for example, as shown in FIG. 4, first, two quartz tubes 1 and 2 of different diameters are connected, and the smaller diameter quartz tube 1 is placed below. The lower end 1a of the small-diameter quartz tube 1 is sealed flat, and the internal heat sink 3 is placed in contact with the inner wall of the small-diameter quartz tube 1.
A solvent 4 is placed on the internal heat sink 3, and a source crystal 5, which is a growth material, is placed on top of the solvent 4, and a large diameter quartz crystal is placed in a high vacuum of about 2×10 ^-7 Torr. By sealing off the upper end of the tube 2, an ampoule 6 for bulk growth is manufactured. By setting the bulk growth ampoule 6 manufactured in this way into a heating furnace (not shown) that is preset to a predetermined temperature, crystals 7 can be grown on the internal heat sink 3 by the temperature difference method. I have to.

However, when crystal growth is performed using the bulk growth ampoule 6 configured as described above, as shown in FIG. grows. This is because the generated heat generated during crystal precipitation flows preferentially in the center of the crystal 7 compared to the periphery as shown by the arrow in FIG. This is because the temperature of the crystal periphery is relatively high compared to the temperature of the center, and the temperature of the crystal periphery is not uniform between the center and periphery of the crystal.

In the case of the above-mentioned convex crystal 7, the diameter of the crystal in the horizontal plane at this convex portion is small and it is not possible to cut out a wafer having a constant uniform diameter, so the convex portion is cut off or It was necessary to scrape it off, and it was not possible to efficiently cut out wafers using 100% of the grown crystal 7.

[Object of the Invention] In view of the above points, an object of the present invention is to provide a liquid phase growth apparatus for semiconductors, which allows crystal growth with a flat top surface.

[Means and actions for solving problems]

The above object, according to the present invention, includes two quartz tubes of different diameters connected to each other, the lower end of a lower first quartz tube of small diameter is flattened, and the first quartz tube is An internal heat sink was attached so as to be in contact with the inner wall of the tube, and the solvent and source crystal were placed in a large-diameter second quartz tube above the internal heat sink, and the upper end of the second quartz tube was sealed under high vacuum. In a semiconductor crystal liquid phase growth apparatus that uses a bulk growth ampoule to grow semiconductor crystals, a hole is provided upward from the lower end of the internal heat sink along its central axis. This is achieved by

According to this device, since the hole is provided along the central axis of the internal heat sink installed in the bulk growth ampoule, the heat conduction efficiency near the center of the upper surface of the internal heat sink is slightly suppressed. The heat of crystal formation flowing through the periphery of the crystal grown on the top surface of the internal heat sink in the bulk growth ampoule is dissipated more efficiently in the periphery of the internal heat sink than in the center. A uniform temperature distribution throughout will be achieved. In this way, uniform crystal growth is performed within the bulk growth ampoule, resulting in a crystal with a flat top surface.

〔Example〕

Hereinafter, the present invention will be explained in detail based on one embodiment shown in the drawings.

FIG. 1 shows a bulk growth ampoule used in an embodiment of a liquid phase growth apparatus for carrying out the present invention. quartz tube 11
and a large-diameter second quartz tube 12 with an inner diameter of 8 to 13 mm, for example, are connected in an upright manner so that the first quartz tube 11 is positioned below, and the lower end of the first quartz tube 11 is For example, an internal heat sink 13 with an outer diameter of 5 to 12 mm and a height of 80 to 200 mm is attached so as to be in contact with the inner wall of the first quartz tube 11, and the internal heat sink 13 is sealed so as to be flat.
After pouring the solvent 14 into the second quartz tube 12 in the bulk growth ampoule 10, and pouring the source crystal 15 of the growth material on top of it, for example, 2×
It is constructed by sealing off the upper end of the second quartz tube 12 in a high vacuum of about 10 ^-7 Torr, and its total height is:
For example, it is 250 to 300 mm.

The above configuration is similar to that of a bulk growth ampoule in a conventional liquid phase growth apparatus.

In the bulk growth ampoule 10 according to the present invention, the internal heat sink 13 is further arranged upwardly from the lower end of the internal heat sink 13 and along its central axis, e.g.
Cylindrical hole 13 of 2.3 to 6 mm and height of 40 to 160 mm
A is provided.

The present apparatus 10 is constructed as described above, and when performing crystal growth, the bulk growth ampoule 10 is set in a heating furnace, and a hole provided along the central axis of the internal heat sink 13 is opened. 13a
Due to the action of the upper surface 1 of the internal heat sink 13
Since the heat conduction efficiency in the central part of the internal heat sink 13 is suppressed, a substantially uniform temperature distribution can be obtained on the upper surface 13b of the internal heat sink 13. Therefore, the crystal 16 grown on the upper surface is as shown in FIG. ,
The top surface has a relatively flat shape.

An experimental example is shown in Figure 3. In the liquid phase growth of ZnSe, the length of the internal heat sink is
100 mm, diameter 5 mm (Comparative Example 1 in Figure 3), the ratio of the height lc at the center of the crystal to the height le at the periphery is lc/le.
is about 1.2 to 1.3, and the length of the internal heat sink
200mm, diameter 5mm (comparative example 2), the ratio lc/le is approximately
1.8 to 1.9, whereas for an internal heat sink with a length of 100 mm and a diameter of 5 mm, the length of the internal heat sink is 80 mm in length and a diameter of 2
When drilling mm holes (experimental example), the ratio lc/le is approximately
It will be about 1.17.

〔Effect of the invention〕

As described above, the present invention includes two quartz tubes of different diameters connected to each other, the lower end of the lower first quartz tube of small diameter is sealed flat, and the lower end of the first quartz tube of small diameter is sealed flat. Attach an internal heat sink so that it is in contact with the inner wall of the quartz tube, place the solvent and source crystal in a large-diameter second quartz tube above the internal heat sink, and seal the upper end of the second quartz tube under high vacuum. In a semiconductor crystal liquid phase growth apparatus for growing a semiconductor crystal using a bulk growth ampoule, a hole is provided upward from the lower end of the internal heat sink along its central axis. Therefore, due to the hole provided along the central axis of the internal heat sink installed in the bulk growth ampoule, the heat conduction efficiency near the center of the upper surface of the internal heat sink is slightly suppressed, and the bulk growth The heat of crystal formation during crystal growth on the upper surface of the internal heat sink in the growth ampoule is dissipated more efficiently in the peripheral area of the internal heat sink than in the central area.

Therefore, a uniform temperature distribution is achieved over the entire top surface of the internal heat sink, thus resulting in uniform crystal growth within the bulk growth ampoule, resulting in a crystal with a flat top surface. The grown crystals are used with high efficiency and cut into wafers.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an embodiment of a liquid phase growth apparatus for carrying out the present invention, FIG. 2 is a diagram showing the shape of a crystal grown by the apparatus of FIG. 1, and FIG.
The figure is a graph showing the height ratio between the center and peripheral parts of a crystal according to an experimental example. FIG. 4 is a schematic cross-sectional view showing an example of a conventional liquid phase growth apparatus, and FIG. 5 is a diagram showing the shape of a crystal grown by the apparatus shown in FIG. 10... Ampoule for bulk growth; 11... First quartz tube; 12... Second quartz tube; 13... Internal heat sink; 13a... Hole; 13b... Top surface of internal heat sink; 14... Solvent; 15... Source crystal; 16... Crystal grown.

Claims (1)

[Claims] 1. It includes two interconnected quartz tubes with different diameters, the lower end of the first quartz tube with a smaller diameter is sealed flat, and the internal heat sink is placed in contact with the inner wall of the first quartz tube. Place the solvent and source crystal in a large-diameter second quartz tube above the internal heat sink, then seal the top end of the second quartz tube in a high vacuum to grow the semiconductor using a bulk growth ampoule. A semiconductor crystal liquid phase growth apparatus for growing a crystal, characterized in that a hole is provided upward from the lower end of the internal heat sink along its central axis. growth equipment.