JPH03193693A - Method for growing mixed crystal of compound semiconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application]
, InGaAs, AlGaAs, HgCdTe, etc. compound semiconductor mixed crystal C growth method.

[Prior Art] Conventionally, compound semiconductor mixed crystals have been obtained by epitaxial growth on a substrate made of a binary compound semiconductor, typically GaAs or lnP, at a temperature of .degree. Furthermore, as a method for growing a compound semiconductor mixed crystal in bulk crystal form, a method disclosed in Japanese Patent Publication No. 52-2344, for example, has also been attempted.

[Problems to be Solved by the Invention] An obstacle to the growth of compound semiconductor mixed crystals is that the composition of the constituent elements changes in the growth direction due to segregation phenomena, making it difficult to efficiently obtain crystals with the desired composition11) It is. As a means to solve this problem, the raw material solution is brought into contact with the solid raw material,
A method of keeping the composition of the raw material solution constant 4 has been devised.

However, this method requires growth at high temperatures based on the premise of growth from a stoichiometric solution, and requires the use of a liquid sealant to suppress the dissociation of constituent elements. [Means for solving the problem] The present invention is applicable to systems having one element as a constituent element, G, which is a constituent element of a compound semiconductor compound mixed crystal.
Binary compound semiconductor crystal GaAs consisting of a and As,
Binary compound semiconductor crystal GaSb consisting of Ga and sb,
Binary compound semiconductor crystal CdTe consisting of Cd and Te
A binary compound semiconductor crystal such as a crystal is charged to the bottom of a raw material solution for growing a semiconductor compound mixed crystal, and the crystal is grown while one of the constituent elements of the mixed crystal is supplied to the raw material solution through the pores. This is a method for growing a compound semiconductor mixed crystal, which is characterized by the step of growing a compound semiconductor mixed crystal.

For example, when growing a N AlGaAs mixed crystal, using a raw material solution with a high composition ratio of Ga allows growth at low temperature, hydrogen atmosphere, and low pressure. In this case, as the crystal grows, the ratio of A1 and As in the raw material solution decreases,
Crystal growth cannot continue at a constant temperature. Therefore, As is supplied by bringing solid GaAs into contact with the raw material solution. By keeping the temperature at the interface between the solution and the GaAs crystal constant, the As necessary for growing the crystal is automatically supplied to the raw material solution. Further, in order to keep the A i in the solution constant at 714 degrees, liquid metal AI is supplied through the pores in accordance with the amount of crystal growth. By the above method, an AlGaAs mixed crystal having a constant A1 composition can be grown.

Hereinafter, implementation of the present invention will be explained. FIG. 1 shows an example of a growth apparatus in which the present invention can be carried out.
Explain the outline.

In the figure, 5 indicates an outer crucible, and 4 indicates an inner crucible, both of which are made of high-purity carbon. A pore 8 is formed in the side wall of the inner crucible 4 at a position where a raw material solution 1 (to be described later) is present, and the pore 8 communicates with the inside and outside. When there is liquid at the bottom of the outer crucible 5, the bottom outer part of the inner crucible 4 acts as a piston, pushing up the liquid at the bottom of the outer crucible 5, and the liquid flows into the pores. 8, and the liquid can be injected into the crucible 4 through the pores 8.

Although not shown, heaters are arranged in sections surrounding the outer crucible 5, and above the inner crucible 4, a pulling shaft 7 that can rotate in the vertical direction is installed. Although not shown, the pulling shaft 7 is attached to a weight sensor, and the inner and outer crucibles and a portion of the pulling shaft 7 are housed in a container.

[Example - GaGa100OGaAs crystal 25.
20g, kl 1. [i0Gg was added. inner crucible 4
1200 g of GaAs crystals with a diameter of 75 mm are charged at the bottom of the tube. On the other hand, 110 g of Ar was charged into the outer crucible 5.

High purity ■2 After heating up to 800℃ in an atmosphere, the secondary shaft 6
, the molten AI solution 3 at the bottom of the crucible 5 is communicated with the lower raw material solution 1 through the pores 8 . After stabilization, the AlGaAs seed crystal 9 set on the pulling shaft 7
was soaked in raw material solution 1 to start growth. The pulling shaft 7 is attached to a weight sensor as described above, so that the weight of the growing crystal can be monitored. The output of the heater is adjusted based on the data on the crystal weight, the diameter of the crystal is controlled, and the A of 0.109 times the weight of the grown crystal is
The subshaft 6 was driven so that the I solution was injected into the raw material solution. Control of the diameter of the grown crystal and driving of the secondary axis were performed by computer control. The seed crystal 9 was an AlGaAs single crystal with an AI group composition of 0.5 with the <100> direction as its axis, and the growth rate was 2 m-/h1 and the rotation speed was Q rpm. The resulting crystal was an ingot with a diameter of 50 cm and a weight of 1 kg. Analysis of the A1 composition in the growth direction in the crystal revealed that it was uniform over the entire region with X=0.5.

In the above embodiment, GaAs crystals were added to the raw material solution.
20g is added, which means that the temperature of the raw material solution is 800.
It is the amount of GaAs that can be dissolved at ℃. In principle, it is possible to start growth without preparing such a GaAs crystal, and after waiting for the Al-Ga solution to be replenished with a saturated amount of GaAs from the bottom of the inner crucible.
In order to more quickly produce an Al--Ga solution containing a saturated amount of GaAs, the method of the above embodiment was adopted.

Next, regarding the growth of AlGaSb mixed crystal, a GaSb crystal is charged at the bottom of the crucible, and Ga, GaSb
The method is carried out by preparing raw material solutions of crystals and AI and supplying an AI melt.

In addition, regarding the growth of InGaAs mixed crystal, an InAs crystal is placed at the bottom of the crucible, and +n, InAs crystal, and Ga are placed on top of it.
It can also be carried out by preparing a raw material solution and supplying a Ga melt, or by preparing a GaAs crystal at the bottom of a crucible and supplying an In melt.

Furthermore, for HgCdTe, it can be carried out by charging HgTe crystals at the bottom of a crucible, preparing a raw material solution of Te, 'F4)Te crystals on top of the crucible, and replenishing the CD solution.

As can be understood from the above embodiments of the present invention, the binary compound semiconductor crystal contained in the ternary compound semiconductor crystal to be grown is charged to the bottom of the crucible filled with the raw material solution, and the We recommend choosing a method that injects elements other than the elements that form the binary compound semiconductor crystal as a liquid, thereby canceling out changes in the composition ratio of the elements that occur when crystals are precipitated from the raw material solution. The crystals are then supplied to the raw material solution at a fixed ratio.

[Effects of the Invention] According to the present invention, the composition for growing a compound semiconductor mixed crystal can be easily controlled, and a large amount of compound semiconductor mixed crystals having a uniform composition can be obtained.

Even when the constituent element is As, a compound semiconductor mixed crystal can be grown at low pressure without using a liquid sealant.

[Brief explanation of drawings]

FIG. 1 shows an apparatus for implementing the invention. 1... Raw material solution, 2... Binary compound semiconductor crystal such as GaAs, 3... Solution such as A1, 4... Inner Ruppo, 5
...outer shaft, 6...secondary shaft, 7...pull shaft,
8... Pore, 9... Seed crystal, 10... 1jGaA
Mixed crystals such as s.

Claims (2)

[Claims] (1) A compound semiconductor mixed crystal characterized in that a binary compound semiconductor crystal is charged at the bottom of a raw material solution, and one of the constituent elements is further supplied to the lower raw material solution through pores while crystal growth progresses. How to grow. (2) Charge GaAs crystals at the bottom of the raw material solution, and then use a piston mechanism to force the Al solution, which is in communication with the raw material solution through pores, into the raw material solution at a constant ratio with the growing crystals. A method for growing an AlGaAs mixed crystal, characterized by progressing crystal growth while supplying the crystal.