JP3021937B2 - Method for producing cadmium manganese tellurium single crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a cadmium manganese tellurium single crystal.

[0002]

(Hereinafter sometimes referred Cd _1-x Mn _x Te single crystal) [Prior Art] Cd _1-x Mn _x Te single crystal of cadmium manganese telluride to over general formula is optical communication, optical information recording, etc. This is a Faraday material used as an optical isolator element for preventing return light of a semiconductor laser, an optical fiber current sensor element, and the like, and is used in the field of different wavelengths due to a difference in composition. In addition, the single crystal is generally Cd, Mn, Te
Using the mixture as a raw material, the mixture is sealed by a Bridgman method in a quartz glass ampoule containing a quartz glass growth crucible whose inside surface is coated with carbon or a quartz glass crucible made of Pyrolyte boron nitride. Manufactured.

[0003]

In the above-mentioned method for producing a Cd _1-x Mn _x Te single crystal by the Bridgman method, when Cd, Mn and Te are reacted in a dissolved state,
In particular, the reaction between Mn and Te raises the temperature and damages the inner surface of the growth crucible. For example, when a quartz glass crucible coated with carbon on the inner surface is used as a growing crucible, the carbon coated on the inner surface of the growing crucible is peeled off, and the Cd _1-x Mn _x Te melt in the growing crucible is removed. It is highly likely that Si reacts with quartz glass during the growth to mix with Si as an impurity in the crystal, resulting in polycrystals.In addition, cracks in the growth crucible cause cracks in the single crystal as well as growth crucibles. May be destroyed and the growth of the single crystal may not be continued.
Further, when a crucible made of Pyrrolitec boron nitride is used as a growth crucible, polycrystallization is not performed as in the former case, but the number of times that the growth crucible can be used is small due to damage to the growth crucible. For example, X = 0 in Cd _1-x Mn _x Te.
In the case of 48 compounds, the growth crucible can be used only about two or three times. Accordingly, it is an object of the present invention to address these issues.

[0004]

SUMMARY OF THE INVENTION The present invention provides a Cd _{1 -X} Mn _X
In the method for producing a cadmium manganese tellurium single crystal in which a single crystal of Cd _1-x Mn _x Te is grown by the Bridgman method in a state in which a Te raw material is sealed in a growth crucible, Mn and Te are previously used as the raw materials. Is from 0.09 to
It is characterized by using a reactant and Cd reacted in a range of 0.48 .

[0005]

In the manufacturing method of the present invention, M
n and Te are reacted in advance in another reaction vessel different from the growth crucible, and a reactant and Cd are used as raw materials.
There is almost no reaction between Mn and Te in the growing crucible.
Therefore, the melt in the growth crucible does not become as hot as before, the carbon coated on the inner surface of the growth crucible is not damaged and exfoliated, and the melt does not react with the quartz glass because it does not react. The constituents of the growing crucible do not mix as impurities in the crystal and do not become polycrystalline, and there is no crack in the single crystal due to cracks entering the growing crucible. The single crystal is not broken and cannot be grown. Further, even when a crucible made of Pyrrolitec boron nitride is used as a growing crucible, the inner surface thereof is less damaged and the life of the growing crucible is improved. For example, Cd _1-X M
n number of times of use in the case of the compound of X = 0.48 in _X Te is 20 times more than the life of two to three times is remarkably improved. Therefore, the single crystal becomes a single crystal having high quality without variation and stable optical characteristics. In particular, one of the raw materials
The reaction product of Mn and Te having a Mn ratio of 0.09 to
Reactant Mn _x Te reacted in the range of 0.48
(0.09 ≦ X ≦ 0.48) and is stable and easily obtained.
Alloy that is easy to produce the desired single crystal
be able to.

[0006]

Embodiments of the present invention will be described below. (Example) Using a reactant of Mn and Te and Cd as raw materials, four types of Cd _1-x Mn _{x of} X = 0.09, 0.13, 0.30 and 0.48
Te single crystals were grown. The reactant of Mn and Te was formed by a general method such as heat melting under an inert gas and arc melting. Further, two types of crucibles A and B shown in FIGS. 1 and 2 were used as the growing crucible. Both crucibles A and B have a bottom apex angle of 40 degrees, an inner diameter of 16 mm, an outer diameter of 18 mm, and a length of 150 mm. The crucible A is a silica crucible having an inner surface coated with carbon. A predetermined amount of the raw material C is put in the crucible A, and the upper part is sealed while evacuation is performed for growth. Further, the crucible B is a crucible made of Pyrotechnic boron nitride, and after a predetermined amount of raw material is put, the apex angle of the bottom is 40 degrees, the inner diameter is 18.2 mm, and the outer diameter is 20 mm.
It is put into an ampoule D made of mm quartz glass, and the upper part of the ampoule D is sealed and cultivated while vacuuming.

A crucible A containing the raw material C and an ampoule D containing the crucible B containing the raw material C are set in a vertical Bridgman furnace to melt the raw material C, and then the single crystal is formed at a speed of 2 mm / hr. Nurtured. For growing, the high temperature part (upper part of the furnace)
The temperature was set at 100 to 1,120 ° C., the low temperature section (the lower part of the furnace) was set at 910 to 930 ° C., and the temperature gradient between the two zones was set at 20 ° C./cm.

(Comparative Example) Growth was carried out under the same conditions as in the above embodiment using both crucibles A and B in the same manner as in the above embodiment, except that Mn, Te and Cd were used alone as raw materials. . However, for those having a high reactivity with the crucible and a large amount of Mn, the growing speed was increased.

(Evaluation of Crystallinity) The optical properties of the single crystals obtained in Examples and Comparative Examples are shown in Tables 1 and 2. The optical characteristics are obtained by evaluating the crystallinity by measuring the extinction ratio. Here, the extinction ratio refers to a method in which a single crystal sample is placed between a polarizer and an analyzer in a crossed Nicols state, and crystallinity is evaluated based on a light scattering state. The larger the numerical value of the extinction ratio is, the better the crystallinity is, and in Tables 1 and 2, the extinction ratio is indicated by the following criteria.

[0010]

[0011]

[Table 1]

[0012]

[Table 2]

(Consideration) As shown in Table 1, when a silica crucible A coated with carbon is used,
It can be seen that the optical characteristics of the single crystal are significantly improved when the method of the present invention is employed. Table 2 shows the results when Crucible B made of Pyrrolitec boron nitride was used.
As can be seen, when the method of the present invention is employed, the number of times the crucible can be used is 20 times or more, and the life of the crucible is significantly improved. The cost of growing a single crystal is reduced by improving the life of an expensive crucible.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a crucible for carrying out the production method of the present invention.

FIG. 2 is a longitudinal sectional view showing another example of the crucible for carrying out the production method of the present invention.

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Claims (1)

(57) [Claims] 1. A Cd _1-X Mn wherein at Bridgman method _X Te raw material in a sealed state to the breeding crucible Cd _1-X Mn _X Te
In the method for producing a cadmium manganese tellurium single crystal for growing a single crystal , Mn and Te are reacted as the raw materials in advance with the ratio of Mn in the range of 0.09 to 0.48.
A method for producing a cadmium manganese tellurium single crystal, comprising using the reacted reactant and Cd .