JP3231050B2 - Compound semiconductor crystal growth method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of growing a compound semiconductor bulk single crystal using a sublimation method or a halogen transport method, and particularly to a II-VI group compound semiconductor (ZnS, ZnSe).
Etc.).

[0002]

2. Description of the Related Art The sublimation method and the halogen transport method are used as bulk single crystal growth methods for compound semiconductors.
In single crystal growth of II-VI group compound semiconductors such as ZnSe, it is possible to avoid the incorporation of crystal polymorphs accompanying the passage of the phase transition point at the time of cooling which is observed in the melting method and the like performed under high temperature and high pressure. It is effective in obtaining a single crystal of high quality. A crystal growth apparatus conventionally used in a crystal growth method such as the sublimation method or the halogen transport method (for example, JP-A-63-3549).
FIG. 3 is a schematic diagram of the above publication. In the figure, 11 is a growth vessel, 12 is a support rod, 13 is a raw material powder, 14 is a seed crystal, 15 is a growth crystal, 16 and 17 are heating furnaces, and 18 is a temperature distribution in the heating furnace. The growth vessel 11 is, for example, a cylindrical vessel made of quartz.
Is filled and seed crystal 1 is formed at the other end formed into a conical shape.
4 is connected to the support rod 12 and installed. Raw material 13
The growth vessel loaded with the seed crystal 14 is set in a vertical or horizontal heating furnace 16 in which the raw material filling region is set at a high temperature (T ₄ ) and the seed crystal 14 is set at a low temperature (T ₅ ). The temperature difference between the material filling region and the crystal growth region (T ₄ −
The transport of the raw material is caused by the flow of the raw material vapor due to T ₅ ), and the growth of the crystal 15 proceeds on the low-temperature seed crystal 14.

When ZnS is grown by the halogen (iodine) transport method using the above-mentioned growth method, a large single crystal having a homogeneous portion of about 10 × 10 × 15 mm ³ is obtained. However, due to the influence of convection in the growth vessel, polycrystal growth or growth on the inner wall of the vessel often occurred. In addition, even when a single crystal is obtained, the shape of the grown crystal may be partially disordered, and the ratio of the obtained single crystal having a uniform shape is about 50% or less.

[0004]

As described above, in the conventional growth method, the space between the raw material filling region and the crystal growth region in the growth vessel is forced to control the gas flow in the vessel. No means is provided, and a single crystal cannot be obtained with good reproducibility due to the influence of convection in the growth vessel, and furthermore, the obtained single crystal also includes disorder in the crystal shape. Had. Moreover, since the influence of convection increases with an increase in the diameter of the growth vessel, the above-mentioned problems become more apparent when the growth vessel is enlarged, and it is extremely difficult to grow a large single crystal with good reproducibility. Was.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a method of growing a compound semiconductor crystal using a sublimation method or a halogen transport method, the method includes: A structure capable of suppressing generation of gas convection in the vessel is provided between the crystal growth area and the crystal growth, and a region between the raw material filling area and the crystal growth area of the growth vessel is provided. By providing at least one lattice plate in the growth vessel, or by arranging a thin tube having an inside diameter smaller than that of the growth vessel tightly bundled with the inside diameter of the growth vessel, generation of convection of the raw material vapor in the growth vessel is prevented. This is a compound semiconductor crystal growth method characterized by suppressing. Immediately
That is, the crystallization of the compound semiconductor according to the present invention (claim 1).
The long method uses a compound semi-conductor using the sublimation method or the halogen transport method.
A method for vapor-phase growth of a body, comprising:
A gas in the growth vessel is provided in a region intermediate with the crystal growth region.
Install internal structures that can suppress the generation of convection
The above problem is solved by growing. this
The compound semiconductor crystal growth method according to the present invention (claim 2)
The internal structure according to claim 1, wherein at least one
The above-mentioned problem is solved by using a lattice plate.
Crystal growth method for compound semiconductor according to the present invention (claim 3)
The said internal structure of Claim 1 is the said growth container.
Made of a thin tube having an inside diameter smaller than the inside diameter of
Thus, the above problem is solved. In this invention (claim 4)
The method for growing a compound semiconductor crystal according to claim 1, 2 or 3.
In the method for growing a compound semiconductor crystal according to
The material installation area must be kept at a higher temperature than the material filling area.
This solves the above problem.

The shape of the growth vessel used in the present invention is preferably cylindrical in view of productivity, pressure resistance, etc., and its size depends on the size of the crystal to be grown (the amount of raw material charged). Practical size (15 × 15
× 15 mm ³ to 75 × 75 × 150 mm ³ ) in order to obtain a crystal having an inner diameter of 20 to 100 mm and a length of 50 to 800 m.
m is preferable. When a lattice plate is used as an internal structure for suppressing the generation of convection in the container, the position of the lattice plate is, for example, about 0.2 to 1 times the inner diameter of the growth container from the set size (growth end) of the grown crystal. By setting the position, the generation of convection in the crystal growth region can be effectively suppressed, and a space necessary for growing a crystal of a set size is preferably secured. Further, when a plurality of lattice plates are provided, it is preferable that the lattice plates are disposed at intervals approximately equal to or less than the inner diameter of the growth vessel from the lattice plate disposed closest to the growth region to the raw material region in order.
As the structure of the lattice plate, for example, a plate having a large number of through holes in a flat plate, or a lattice-like structure can be used. The size of the through hole or the opening of the lattice is sufficiently smaller than the inner diameter of the growth vessel (1/5 or less), so that the suppression of convection can be sufficiently suppressed.

On the other hand, a bundle of thin tubes is set in a growth vessel,
In the case of suppressing the generation of convection, the installation position may be set at an interval of about 0.2 to 1 times the inner diameter of the growth vessel from the set size of the grown crystal, as in the case of using the lattice plate. preferable. In addition, the inner diameter is 1 of the inner diameter of the growth vessel.
/ 5 or less. Regarding the temperature distribution at the time of growth, for example, a step-like two-temperature distribution in which a high-temperature raw material region and a low-temperature crystal growth region are each maintained at a uniform temperature and a steep temperature gradient is provided between the two temperature regions is used. Alternatively, a temperature distribution in which the temperature of the intermediate region is set to be slightly higher than that of the raw material region is used in order to surely suppress the generation of natural nuclei in a structure for suppressing convection installed in the intermediate region.

[0008]

[Function] By installing an internal structure acting on the gas flow in the vessel in a region between the raw material filling region and the crystal growth region of the growth vessel, generation of convection of the source vapor in the growth vessel is suppressed. As a result, it has become possible to grow a single crystal having a uniform shape with good reproducibility. In particular, when a growth vessel having a large diameter is used, it is remarkable to suppress the generation of convection, and it has become possible to grow a single crystal larger than before.

[0009]

【Example】

Example 1 FIG. 1 is a schematic view of a crystal growth apparatus used in the compound semiconductor crystal growth method of the present invention. In the figure, 1 is a growth vessel, 2 is a support rod, 3 is a raw material powder, 4 is a seed crystal, 5 is a growth crystal, 6 is a lattice plate, 7 is a heating furnace, and 8 is a temperature distribution of the heating furnace. The growth vessel 1 is basically a quartz cylindrical vessel similar to the conventional example as shown in FIG. 4 and has an inner diameter of 50 mm, a length of 200 mm, and a distance of 60 mm and 85 mm from the flat-ended bottom. , 110mm, 135mm, about 2m thick with many through holes of about 3mm in diameter
An m grid plate was installed. In the case of the sublimation method, the raw material powder was filled in the bottom of the vessel, and the seed crystal 4 was fixedly supported by the support rod 2 at the top of the end of the cone and placed. In the case of the halogen transport method, halogen as a transport medium was further filled. The growth vessel, a raw material filling region, grid plate installation area (intermediate area), three regions of the crystal growth region, respectively, T _1, T
_The growth was carried out by holding in a heating furnace 7 having a temperature distribution 8 maintained at a uniform temperature of ₂ , T ₃ (T ₂ ≧ T ₁ > T ₃ ).

According to this embodiment, the iodine is used as a transport medium.
When ZnS is grown by the logen transport method, high purity ZnS
Raw material powder (200 g), iodine, and seed crystal (7 m
mx 7 mm (111) A oriented ZnS single crystal piece)
Sealed in a long container,₁= 850 ° C, middle
Region temperature T_Two= 855 ° C., crystal growth region temperature T_Three= 84
Keep for 30 days in a temperature distribution set at 0 ° C
To form a homogeneous part of about 30 mm x 30 mm x 40 mm.
Large ZnS balm with a well-defined shape that can squeeze almost 85% of the crystal
Quartz single crystals were obtained with a high probability of 80% or more. Embodiment 2 FIG. 2 is a schematic view of a growth apparatus used in a second embodiment of the present invention.
Is shown. In the figure, 1 is a growth vessel, 2 is a support rod, 3 is
Raw material powder, 4 is a seed crystal, 5 is a grown crystal, 9 is a capillary bundle
Except for the bundle of tubules 9 provided in the intermediate region of the growth apparatus.
This is the same as the growth container shown in the first embodiment. Thin tube bundle 9
Is quartz with an inner diameter of 3 mm, a wall thickness of 0.5 mm, and a length of 70 mm
Place the capillary in the middle area 60-130 mm from the bottom of the growth vessel.
In the area, it is installed tightly bundled in the inside diameter of the growth vessel.
As the temperature distribution of the heating furnace, the same step-like shape as in Example 1 was used.
Can be used. Alternatively, hot material charging
Temperature gradient between filling region and low temperature crystal growth region
An inclined temperature distribution 10 can also be used. This growth
In the case of using a container, iodine transport was performed in the same manner as in Example 1.
Growth of large bulk single crystal of ZnS by reproducible method
I was able to. Example 3 Using the crystal growth method of the present invention, ZnSe was formed by a sublimation method.
Grew. Example 1 or Example 1
Use the same shape and size as 2
Purified ZnSe powder (150 g) was used as seed crystals (1
11) Small ZnSe single crystal (10mm × 10mm)
Filling, raw material area temperature 920 ° C, growth area temperature 900
℃, temperature gradient in the middle region 2 ° C / cm in gradient temperature distribution
Grow in. 20x20x3 with about 30 days of growth
0mm^ThreeReproducibility of large single crystal with homogeneous part
I was able to get good. Example 4 Using the crystal growth method of the present invention, Zn was transported by the iodine transport method.
S_0.4Se_0.6Grew. Growth vessels or
The temperature distribution of the heating furnace is the same as in Example 1 or 2.
Using. High purity ZnS and ZnSe powder as raw material
Are mixed and fired at a molar ratio of 4: 6, and are used as seed crystals.
ZnS on (111) A plane_0.4Se_0.6Single crystal piece
It was sealed in a growth container together with iodine. The growth depends on the temperature of the raw material
850 ° C, growth temperature 840 ° C, temperature gradient in the middle area
Growing for about 30 days in 1.5 ° C / cm inclined temperature distribution
30 × 30 × 40mm^ThreeZnS_0.4
Se _0.6A single crystal was obtained with good reproducibility. In addition,
The mixed crystal composition of the grown ZnSSe single crystal depends on the
Of the same composition, and those of the entire mixed crystal composition range
Good reproducibility was obtained. Also, the composition roses in the crystal.
With less than 0.1%, highly homogeneous mixed crystal is obtained.
I was able to. Example 5 Using the crystal growth method of the present invention, Zn was transported by the iodine transport method.
_0.5Cd_0.5S growth was performed. Growth vessels or
The temperature distribution of the heating furnace is the same as in Example 1 or 2.
Using. High purity ZnS and CdS powder as raw material
A mixture at a molar ratio of 1: 1 was used as a seed crystal (11
1) Zn on A side_0.5Cd_0.5Small piece of S single crystal with iodine
Both were sealed in a growth vessel. The growth is performed at a raw material temperature of 800
℃, growth part temperature 792 ℃, middle area temperature 803 ℃
By growing for about 30 days in a step temperature distribution, 30
× 30 × 40mm^ThreeZn_0.5Cd_0.5Reproduce S single crystal
I was able to get good. Also in this embodiment, Embodiment 4
All sets are based on the raw material charge composition as in the growth of ZnSSe
ZnCdS in the range of growth can be grown with good reproducibility
Was. Example 6 Using the crystal growth method of the present invention, Zn was transported by the iodine transport method.
_0.3Cd_0.7S_0.4Se_0.6Grew. Growth volume
Example 1 or 2
The same one as described above was used. High purity ZnS, Zn as raw materials
Se, CdS and CdSe powder were added at 6: 9: 14: 2
What was mixed and fired at a molar ratio of 1 was used as a seed crystal (11
1) Zn on A side_0.3Cd_0.7S_0.4Se_0.6Single crystal small
The pieces were sealed in a growth vessel with iodine. Growth is a raw material
Temperature 820 ° C, growth temperature 812 ° C, temperature in the middle area
Grow for about 30 days in a stepwise temperature distribution of 822 ° C
30 × 30 × 40mm^ThreeZn_0.3Cd_0.7
S_0.4Se_0.6A single crystal was obtained with good reproducibility.
In this embodiment, the ZnSSe of Examples 4 and 5 or
Total composition by raw material composition as well as ZnCdS growth
Range of ZnCdSSe can be grown with good reproducibility.
Came.

[0011]

According to the present invention, in a method for growing a compound semiconductor crystal using a sublimation method or a halogen transport method, the generation of convection of a source vapor in a growth vessel by a plurality of gas flows is suppressed. Crystals can be grown efficiently and with good reproducibility, and it is possible to provide industrially practical compound semiconductor crystals of a size and crystal quality as crystal materials for compound semiconductor devices and epitaxial growth substrates. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a growth apparatus used in a compound semiconductor crystal growth method according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a growth apparatus used in a second embodiment of the present invention.

FIG. 3 is a schematic view of a growth apparatus used in a conventional compound semiconductor crystal growth method.

[Explanation of symbols]

 Reference Signs List 1,11 Growth container 2,12 Support rod 3,13 Raw material powder 4,14 Seed crystal 5,15 Growth crystal 6 Lattice plate 7,16,17 Heating furnace 8,18 Temperature distribution in heating furnace 9 Thin tube bundle

Continuation of the front page (56) References Japanese Utility Model Showa Sho 61-43275 (JP, U) Phys. Chem. Solids, Pergamon Press, 1946, Vol. 25, p. 187-190 (58) Fields investigated (Int.Cl. ⁷ , DB name) C30B 1/00-35/00 C23C 16/00-16/56 H01L 21/205

Claims (5)

(57) [Claims] 1. A method for vapor-phase growth of a compound semiconductor using a sublimation method or a halogen transport method, wherein a plurality of airflows flow in a region between a raw material filling region and a crystal growth region in a growth container. Can suppress the generation of convection of the gas inside,
A method for growing a compound semiconductor crystal, comprising: installing an internal structure having a plurality of through holes extending from a raw material filling region to a crystal growth region, and performing vapor phase growth. 2. A method for vapor-phase growth of a compound semiconductor using a sublimation method or a halogen transport method, wherein a plurality of airflows flow in a region between a raw material filling region and a crystal growth region in a growth container. Can suppress the generation of convection of the gas inside,
A method for growing a crystal of a compound semiconductor, comprising: installing an internal structure comprising at least one lattice plate and performing vapor phase growth. 3. A method for vapor-phase growth of a compound semiconductor using a sublimation method or a halogen transport method, wherein a plurality of airflows flow in a region between a raw material filling region and a crystal growth region in a growth container. Can suppress the generation of convection of the gas inside,
A method for growing a crystal of a compound semiconductor, comprising: installing an internal structure comprising a plurality of thin tubes having an inner diameter smaller than the inner diameter of a growth vessel and performing vapor phase growth. 4. The method according to claim 1, wherein the internal structure comprises a plurality of capillary bundles. 5. The method according to claim 1, wherein the internal structure installation region is maintained at a higher temperature than the raw material filling region.