JPH0431385A - Device of growing crystal - Google Patents

Abstract

PURPOSE:To grow semiconductor crystal of multiple mixed crystal having uniform composition by equipping a device of growing crystal with a growing solution reservoir having the bottom of an inverted conical surface, a supply solution reservoir and a supply channel for connecting both the reservoirs. CONSTITUTION:A growing solution 1 is a solution of In-Ga-As (molar ratio of the components is 0.875:0.032:0.093), a supply solution 2 is a solution of In-Ga- As (previously made rich in Ga and As), both the solutions have about 700 deg.C, seed crystal 3 is InP, a solute supply material 4 is GaAs and the seed crystal 3 is pulled up by a seed crystal transferring means 17 to grow crystal. Since Ga and As of solute in the growing solution 1 are consumed with growth of the crystal, a DC current is sent from an electrode 15 to an electrode 16, Ga and As are supplied from the supply solution 3 to the growing solution 1 and uniformity of composition of growing crystal is maintained. In the operation, the composition of the growing solution 1 is monitored by a value of resistance and an amount of solute supplied is controlled by changing the value of electric current.

Description

[Detailed Description of the Invention] [Summary] A crystal growth device capable of growing a crystal of a multi-component mixed crystal semiconductor with a uniform composition, regarding a crystal growth device, particularly a device for growing a crystal of a mixed crystal semiconductor from a liquid phase. [1] A crucible 11 including a growth solution reservoir 12, a replenishment solution reservoir 13, and a replenishment groove 14 connecting the growth solution reservoir 12 and the replenishment solution reservoir 13. However, the bottom surface of the growth solution reservoir 12 is configured to have a substantially inverted conical surface.

[21 In [1] above, electrodes 15 and 16 are arranged in the growth solution reservoir 12 and the replenishment solution reservoir 13, respectively, and during crystal growth, the growth solution 1 and the replenishment solution 2 are
The configuration is such that electricity is applied between the

[Industrial application field]

The present invention relates to a crystal growth apparatus, and particularly to an apparatus for growing mixed crystal semiconductor crystals from a liquid phase.

In recent years, remarkable progress has been made in optical semiconductor devices and ultrahigh-speed semiconductor devices using mixed crystal semiconductors, particularly -V group semiconductor mixed crystals. These devices often require a ternary mixed crystal semiconductor, but in that case, it is generally made on a wafer of a binary mixed crystal semiconductor such as GaAS or InP.
A ternary mixed crystal that lattice-matches this is grown. However, in order to expand the range of applications of mixed crystal semiconductors, it is necessary to create multi-component mixed crystal semiconductors with arbitrary lattice constants, not limited to lattice matching with existing binary mixed crystals. It is desired to develop a crystal growth apparatus that can pull homogeneous crystals.

[Conventional technology]

An example of a conventional crystal growth apparatus developed for multi-component mixed crystals will be explained with reference to FIG. FIGS. 2(a) and 2(b) are schematic diagrams of main parts showing an example of a conventional crystal growth apparatus, and FIGS.
) is a side sectional view, and (b) is a top view of the crucible. In the figure, 1 is a growth solution, 2 is a replenishment solution that supplies solute to the growth solution 1, 3 is a seed crystal, and 4 is a solute replenisher. 21
A growth solution reservoir 2 which is a crucible and contains a growth solution 1
2, a replenishment solution reservoir 23 that accommodates the replenishment solution 2, and a replenishment groove 24 that connects the two. Growth solution reservoir 2
The bottom surface of 2 is flat. 15.16 is the electrode, 17
18 is a seed crystal moving means, and 18 is a solute replenishment material moving means.

A heating means is provided around the crucible 21 (not shown).

To grow InGaAs crystals using this equipment,
The seed crystal 3 is made of InP, the solute replenishing material 4 is made of GaAs, and the seed crystal 3 is gradually pulled up by the seed crystal moving means 17 to grow the crystal. As the crystal grows, the solutes Ga and As in the growth solution 1 are depleted, so a current is passed between the electrodes 15 and 16 to replenish these from the replenishment solution 2 to the growth solution 1, thereby increasing the growth of the growing crystal. Maintain uniformity of composition.

[Problem to be solved by the invention]

In order to grow a multi-component mixed crystal semiconductor with a uniform composition, it is necessary to quickly replenish the solute in the growth solution that is lacking in the growth solution to keep the composition of the growth solution constant.

For this purpose, the effect of solute replenishment appears more quickly when the amount of growth solution is smaller.

However, in a crystal growth apparatus like the one shown in Figure 2, when the growth solution reservoir is made shallow to reduce the amount of growth solution, the surface of the growth solution becomes spherical due to surface tension. There was a problem in that the depth could not be made too shallow, and as a result, a crystal with a sufficiently uniform composition could not be grown.

SUMMARY OF THE INVENTION An object of the present invention is to solve such problems and provide a crystal growth apparatus capable of growing a multi-component mixed crystal semiconductor crystal with a uniform composition.

[Means to solve the problem]

This purpose, according to the invention, is achieved by: [1] Growth solution reservoir 12
, a replenishment solution reservoir 13 , and a replenishment groove 14 connecting the growth solution reservoir 12 and the replenishment solution reservoir 13 , and the bottom surface of the growth solution reservoir 12 has a substantially inverted conical surface. [2] In the above [11], the growth solution reservoir 12
And the replenishment solution reservoir 13 has electrodes 15 and 16, respectively.
This can be achieved by providing a crystal growth apparatus which is characterized in that a current is applied between the growth solution 1 and the replenishment solution 2 during crystal growth.

[Effect]

The smaller the amount of growth solution, the more quickly it will be possible to respond to changes in composition, but if the growth solution reservoir is made shallow, the solution surface will form a spherical surface due to surface tension, so a certain depth is required.

In the present invention, by changing the bottom surface of the growth solution reservoir from a conventional flat surface to an inverted conical surface, the volume can be reduced without changing the depth, and therefore the response to compositional changes can be made faster.

〔Example〕

An embodiment of a crystal growth apparatus for mixed crystal semiconductors according to the present invention will be described with reference to FIG.

FIGS. 1(a) and 1(b) are schematic diagrams of main parts of an apparatus according to an embodiment of the present invention, in which FIG. 1(a) is a side sectional view and FIG. 1(b) is a top view of a crucible. In the figure, ■ is a growth solution, 2 is a replenishment solution that replenishes solute to the growth solution 1, 3 is a seed crystal, and 4 is a solute replenishment material. 11 is a carbon crucible, the surface of which is coated with holon nitride (PBN) (for insulation). This crucible 11 includes a growth solution reservoir 12 containing a growth solution 1, a replenishment solution reservoir 13 containing a replenishment solution 2,
It is provided with a replenishment groove 14 that connects the two. The bottom surface of the replenishment solution reservoir 13 has an inverted conical surface. Reference numerals 15 and 16 are electrodes for supplying electricity between the growth solution 1 and the replenishment solution 2, both of which are made of carbon. 17 pulls the seed crystal-
18 is a solute replenishment material moving means. A heating means is provided around the crucible 11 (not shown).

Using this crystal growth apparatus, InGaAs (Ino,
An example of growing a single crystal of 5:l GaO, 47AS) will be described. Growth solution 1 was an In-Ga-As solution (the molar ratio was 0.875:0.032:0.
093), replenishment solution 2 is also an In-Ga-As solution (however, Ga and As are enriched in advance), the temperature of both solutions is about 700°C, the seed crystal 3 is InP, and the solute replenisher 4 is
is GaAs, and the seed crystal 3 is pulled up by the seed crystal moving means I7 to grow the crystal. As the crystal grows, the solutes Ga and As in the growth solution 1 are depleted, so a direct current is passed from the electrode 15 to the electrode 16 to replenish them from the replenishment solution 2 to the growth solution 1, thereby changing the composition of the growing crystal. Maintain uniformity. At this time, the composition of the growth solution 1 is monitored by its resistance value, and the above-mentioned current value is changed to adjust the amount of solute replenishment.

The inventor adjusted the amount of solute replenishment by changing the above current value in the range of 18 to 20 A, and adjusted the pulling rate to 0.1 mm/h.
Ino, Ii3 G with a thickness of 3 mm over 30 hours at r
As a result of growing a single crystal of 47As, the change in composition in the thickness direction could be suppressed to 0.5% or less.

The present invention is not limited to the above embodiments (and can be implemented with various modifications. For example, the present invention is effective even if the bottom surface of the growth solution reservoir is an inverted polygonal pyramid surface. It is also effective to use alternating current as the current source.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a crystal growth apparatus capable of growing a crystal of a multi-component mixed crystal semiconductor having a uniform composition.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the main parts of an apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of the main parts of a conventional crystal growth apparatus. In the figure, l is a growth solution, 2 is a replenishment solution, 11 is a crucible, 12 is a growth solution reservoir, 13 is a replenishment solution reservoir, 14 is a supply groove, and 15 and 16 are electrodes. ” Fig. 1 is a schematic diagram of the main parts of an apparatus according to an embodiment of the present invention.

Claims (1)

[Claims] [1] Growth solution reservoir (12) and replenishment solution reservoir (13)
, the growth solution reservoir (12) and the replenishment solution reservoir (13).
a replenishment groove (14) connecting the crucible (11).
), the bottom surface of the growth solution reservoir (12) forming a substantially inverted conical surface. [2] Electrodes (15, 16) are arranged in the growth solution reservoir (12) and the replenishment solution reservoir (13), respectively, and during crystal growth, the growth solution (1) and the replenishment solution (2)
2. The crystal growth apparatus according to claim 1, wherein a current is applied between the crystal growth apparatus and the crystal growth apparatus.