JPS62138393A - Growth of compound semiconductor mixed crystal - Google Patents

Abstract

PURPOSE:To reduce time for crystal growth in the stage of growth of a compound semiconductor mixed crystal by the liquid encapsulated Czochralski method by inserting a stirring plate into the melt for over a specified time after melting the starting materials, stirring the melt by revolving the crucible, then executing pulling thereafter. CONSTITUTION:Starting materials (e.g. crystals of GaAs and GaP) for the growth of compound semiconductor mixed crystal are charged to a crucible 2 in a high pressure vessel 1, and the starting materials are encapsulated with an encapsulating material 6. Then, the vessel 1 is evacuated and pressurized with inert gas, and the starting materials are melted by heating with a heater 5. Then, a movable bar 9 is inserted from the top of the vessel 1, and a stirring plate 10 fitted to the tip of the bar is dipped in the melt 3, and the melt 3 is stirred by revolving the crucible 2 for over a fixed time by the aid of a susceptor 4. By this method, the temp. condition of the crucible 2 is stabilized within a short time. Thereafter, the movable bar 9 is pulled out and the growth of a compound semiconductor mixed crystal is executed by pulling while allowing a seed crystal 8 to contact with the melt 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for growing a compound semiconductor mixed crystal by pulling it using a liquid-sealed pulling method.

[Conventional technology]

I nAs xP 1- x + GaAs xP 1
Compound semiconductor mixed crystals such as -x are important materials in manufacturing high-speed devices, optical devices, etc. In order to grow these mixed crystals, conventionally, crystal growth is often performed by a vapor phase growth method. However, crystal growth using the vapor phase growth method has a slow growth rate, and for crystal growth that requires a thick growth layer, such as crystals used as substrates, the method of growing crystals using the pulling method is advantageous in terms of growth speed, etc. It is. For this reason, attempts have been made to grow compound semiconductor mixed crystals using the liquid-sealed pulling method. To explain the growth of a mixed crystal by the liquid seal pulling method using the growth of a GaAs 1-, PK crystal as an example, as shown in FIG.
A luribo 2 made of BN or the like is installed, and a crystal of GmA@ and GaP, which is a mixed crystal material to be grown, is placed in the brim of the luribo. The crucible 2 is supported by a susceptor 4 and is heated by a heater 5.
heated by. 6 is boron oxide for sealing, 7 is a pulling shaft, and 8 is a seed crystal. After melting the raw material, the seed crystal 8 is lowered, brought into contact with the raw material melt 3 through the boron oxide for soil 6, and by controlling the temperature of the melt 3 and pulling up the 81 crystal 8 while rotating at a predetermined pulling speed. Growing mixed crystals.

[Problem that the invention seeks to solve]

By the way, when growing a compound semiconductor mixed crystal using such a method, after the raw material crystal is melted, the temperature of the melt is adjusted to a temperature slightly lower than the liquidus temperature of the melt, and the seed crystal 8 is placed on the surface of the melt. The temperature of the melt at this time is most important; if the temperature of the melt is too high, the seed crystal 8 will melt, and if it is too low, the growing crystal will become polycrystalline. grow up.

In particular, when a mixed crystal is pulled up and grown from a melt, the liquidus temperature of the melt sometimes appears to change over time for a long time after melting the raw materials. For this reason,
There is a problem that the temperature conditions for bringing the seed crystal 8 into contact with the melt 3 fluctuate, and up until now, the melt diameter of the raw material has been left alone for a long time, and then the seed crystal 8 has been brought into contact with the melt 3 to perform pulling growth. However, there was a drawback that it took a very long time from the time the raw materials were melted until the pulling growth started.

An object of the present invention is to provide a method for growing a compound semiconductor mixed crystal from a melt by a pulling method, which eliminates these conventional drawbacks.

[Means to solve the problem]

In the present invention, when a p-mix crystal is grown from a melt using the liquid-sealed pulling method, a stirring plate is inserted into the melt for a certain period of time after the raw material crystal is melted, and the crucible is rotated. This is a method for pulling growth of a compound semiconductor mixed crystal, which is characterized by stirring the melt, and then bringing a seed crystal into contact with the melt to perform pulling growth.

〔Example〕

An example in which an embodiment of the present invention is applied to the growth of a GaAm1-xPX mixed crystal will be described below with reference to FIG.

Components that are the same as those in FIG. 2 will be described using the same numbers.

As shown in FIG. 1, GaAm synthesized in advance as a raw material for crystal growth is contained in a PBN melt 2 in a high-pressure vessel 1.
and a GaP crystal in a molar ratio of 9 corresponding to the intended composition of the crystal to be grown, and on top of this, boron oxide 6 as a sealant is added. Next, after evacuating the inside of the container 1, the pressure is increased to several atmospheres with Ar gas, and the temperature of the heating heater 5 is gradually increased. After the boron oxide 6 placed on the raw material is melted, the pressure is increased to 30 atmospheres, and the temperature is further increased. death,
The raw materials were melted. A movable rod 9 is inserted from the top of the raw material melting diameter container 1.
was inserted, and the stirring plate 10 attached to its tip was kept immersed in the melt 3, and the susceptor 4 was rotated at a speed of 1 Orpm for 30 minutes. Thereafter, the movable rod 9 was pulled out of the melt 3, and the seed crystal 8 was brought into contact with the melt 3 by a predetermined operation to perform pulling growth of the crystal. As a result, it was confirmed that the temperature conditions when the seed crystal was brought into contact with the solution were stabilized in a short period of time. Without this treatment, it remained unstable even after several hours. For this reason, compared to the conventional method,
The time from melting the raw material to bringing the seed crystal into contact with the melt surface has been greatly shortened, and the ability to single-crystallize the growing crystal has also been improved.

In the above embodiments, the growth of a GaA m 1 ++ xPx mixed crystal was explained as an example, but it is clear that the present invention can also be applied to the growth of other quaternary mixed crystals such as InAs1-xPx.

〔Effect of the invention〕

As described above, when pulling and growing a mixed crystal from a melt using the liquid sealing method, the method of the present invention can greatly shorten the crystal growth time and also perform stable seeding operations. It has the effect that it can.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an apparatus used in an embodiment of the method of the present invention, and FIG. 2 is a sectional view of a liquid-sealed pulling device. 1... High pressure container, 2... PBN crucible, 3... Feed melt, 4... Susceptor, 5... Heating heater,
6... Boron oxide for sealing, 7... Shaft for pulling, 8
... Seed crystal, 9... Movable rod, 10... Stirring plate. Figure 2

Claims (1)

[Claims] (1) In a method of growing a compound semiconductor mixed crystal from a melt in a crucible using the liquid-sealed pulling method, a stirring plate is inserted into the melt for a certain period of time or more after the raw materials are melted, and the crucible is rotated. 1. A method for growing a compound semiconductor mixed crystal, which comprises stirring a melt and then bringing a seed crystal into contact with the melt to perform pulling growth.