JPS60239386A - Process for preparing single crystal - Google Patents

Abstract

PURPOSE:To prepare a single crystal uniformly doped in the crystal in the process for synthesizing single crystal by the light collecting floating zone method by increasing the concn. of a doping agent at a tip part of a starting material bar. CONSTITUTION:In the prior art for synthesizing a single crystal by the light collecting floating zone method, unifrm doping has failed frequently, resulting in low concn. of the doping agent in the initial stage and gradually increasing the concn. of the doping agent as the growth of the single crystal proceeds if a doping agent having a small distribution coefft. in the mother crystal and a starting material bar having uniform concn. of the doping agent are used. Uniform concn. of the doping agent in the whole part of the crystal has become possible by increasing the concn. of the doping agent at the tip of the starting material bar.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention focuses on a light focusing zone (hereinafter referred to as F).

2.) This relates to the production of single crystals by the method.

[Prior art]

Conventionally, when synthesizing a crystal doped with a substance with a small distribution coefficient with respect to the mother crystal using the light-concentrating floating zone method, when a raw material rod with a uniform concentration is used, the concentration of the doping agent in the crystal is initially low, but gradually increases as it grows. There was a problem that the concentration was high and it was not possible to dope uniformly.

〔the purpose〕

An object of the present invention is to uniformly dope a substance having a small distribution coefficient with respect to the host crystal using the condensing F, Z method.

〔overview〕

In the present invention, an attempt was made to uniformly dope into the crystal by increasing the concentration of the doping agent at the tip of the raw material rod. At this time, the concentration and amount of the tip portion vary depending on the material and diameter of the crystal. The remaining concentration may be set to the desired doping concentration of the crystal. [Example] <Example 1> An alexandrite single crystal was synthesized.

0 Raw material rod composition Tip portion BeO5,00231F h1.2o, 2o3922f Fθ203 3.193EI Cr203 '0608C1f Remainder BeO'5.0023ft Aλ20. 20J922S' lPe203 060685' 0r2030.12169 0 Production of raw material rod Each of the above raw material powders is weighed into an alumina mortar and mixed thoroughly. Next, weigh 1.52 of the raw material powder at the tip and φ
Pack into 8WIL rubber tube. Next, the remaining raw material powder is packed, air is removed from the tube, and the tube is molded into a rod with a diameter of 7 mm x 100 gB (ffi) using a rubber press method. This is sintered in an electric furnace at 1600°C for 4 hours.

0 Crystal Synthesis Using the above raw material rod, synthesize crystals under the following synthesis conditions using the experimental apparatus shown in Figure 1.0 Growth direction: (
001) Growth atmosphere: Air 1 Shaft rotation speed: 30 rpm (upward, downward, reverse rotation) Growth rate: 10 words/H Growth time: 48 hours 0 Results and findings Uniformly colored alexandrite single crystals were synthesized. Further, when this crystal was cut parallel to the growth direction and the concentration of iron and chromium was analyzed along the growth direction using a Xi microanalyzer (X0M, A), it was found that iron and chromium were uniformly present.

<Example 2> Synthesized alexandrite single crystal.

0 raw material rod composition Both the tip portion and the remaining portion follow <Example 1>.

0 Raw material rod production <Example 1 except that a rubber tube with a diameter of 10 g was used, the diameter of the raw material rod was set to 10 strokes (φ), and the amount of the tip was 292 mm.
> Follow.

0 crystal synthesis According to <Example 1>.

0 Results and Observations Uniformly colored alexandrite single crystals were synthesized. Analyzed by XMA in the same manner as in Example 1>,
Iron and chromium were uniformly present.

<Example 3> 〇〇 Raw material rod composition for synthesizing single crystal of green sapphire Tip part p, I/, 2o336.01i' Oo 0 4. OS' Remainder AλzOs 3B, 8f Oo O1, 2S' 0 Preparation of raw material rod The above raw material powders are each weighed into an alumina mortar and mixed thoroughly. Next, weigh out 3.01 mm of raw material powder at the tip and φ1
Pack into a 0gIIk rubber tube. Next, the remaining raw material powder is packed, air is removed from the tube, and the tube is molded into a keyaki of 8 jll (φ) x 10 o m (A) by a rubber press method. This is sintered in an electric furnace at 1600°C for 4 hours.

0 Crystal Synthesis Using the raw material rod described above, crystals were synthesized under the following synthesis conditions using an experimental apparatus as shown in FIG.

Growth direction: (1, o o) Growth atmosphere: Hydrogen Rotation speed of shaft: 30 rpm (upward, downward, reverse rotation) Growth rate = 1.0 words/H Growth time: 48 hours 0 Results and findings Uniform coloring A single crystal of green sapphire was synthesized. Further, when analyzed by XMA in the same manner as in <Example 1>, cobalt was uniformly present.

〔effect〕

The effect of the present invention is that by increasing the concentration at the tip of the raw material rod, the entire crystal can be doped uniformly.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the experimental apparatus used in the present invention. 1...Spheroidal mirror 2...Halogen lamp 3...Quartz tube 4... Atmosphere gas inlet 5... Atmosphere gas outlet 6...Raw material rod 7... Seed crystal 8... Melting zone 9... Main spindle shaft 10... Main spindle lower shaft that's all Applicant: Suwa Seikosha Co., Ltd. Figure 1

Claims (1)

[Claims] 1. A method for producing a single crystal, which comprises increasing the concentration of a doping agent at the tip of a raw material rod in crystal synthesis using a light-concentrating 70-ting zone method.