Preparation method of low-stress and high-purity semi-insulating SiC single crystal

A low-stress, single crystal technology, applied in the direction of single crystal growth, single crystal growth, chemical instruments and methods, etc., can solve the problem of large overall equipment investment, and achieve low equipment investment, low micropipe density, and small crystal stress Effect

Active Publication Date: 2016-08-03
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, most of the specific gases introduced during growth are dangerous gases, and special pipelines, exhaust gas treatment and discharge equipment need to be equipped, so the overall investment in equipment is relatively large

Method used

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  • Preparation method of low-stress and high-purity semi-insulating SiC single crystal
  • Preparation method of low-stress and high-purity semi-insulating SiC single crystal

Examples

Experimental program
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Effect test

Embodiment 1

[0053] A method for growing a low-stress high-purity semi-insulating SiC single crystal, the steps are as follows:

[0054] Step 1: Synthesis of high-purity SiC powder

[0055] (1) Put the thermal insulation material of the synthetic material into the growth furnace for pretreatment, heat it to 1800°C, keep it warm for 5 hours, and then slowly lower it to room temperature. Repeat 2 times in a row to ensure that the boron in the heat preservation is no longer released in subsequent synthetic material furnaces, so as to prevent boron impurities from melting into the SiC powder.

[0056] (2) Mix high-purity silicon powder and carbon powder evenly in a molar ratio of 1:1, put them in a graphite crucible with a coating on the surface, and seal the crucible. Put the crucible, insulation material, etc. into the growth chamber, and seal the furnace mouth.

[0057] (3) Vacuumize the growth chamber for 15 hours to make the vacuum degree reach 10 -5 After Pa, raise the temperature to ...

Embodiment 2

[0075] A method for growing a low-stress high-purity semi-insulating SiC single crystal, as described in Example 1, the difference is that

[0076] Step 1: Synthesis of high-purity SiC powder

[0077] The pretreatment temperature of the heat preservation material is 1900°C, and after 10 hours of heat preservation, it is slowly lowered to room temperature. Vacuum the growth chamber for 5 h to make the vacuum degree reach 10 -4 Pa, raise the temperature to 1000°C, continue vacuuming for 10 hours, and make the vacuum degree reach 10 -4 After Pa, increase the temperature to 1500 degrees, and continue vacuuming for 10 hours to make the vacuum degree reach 10 -4 Pa. Then, a mixed gas of argon and hydrogen was introduced, the pressure was 900 mbar, and the temperature was raised to 1800° C. for synthesis, and the synthesis time was 10 hours.

[0078] Step 2: Crystal Growth

[0079] The pretreatment temperature of the insulation material is 2400°C, and the insulation is kept for ...

Embodiment 3

[0082] As described in Example 1, each step operation is as described in Example 1, the difference is:

[0083] Step 1: Synthesis of high-purity SiC powder

[0084] The pretreatment temperature of the heat preservation material is 1850°C, and after 8 hours of heat preservation, it is slowly lowered to room temperature. Vacuum the growth chamber for 8 hours to make the vacuum degree reach 5×10 -5 Pa, raise the temperature to 950°C, continue vacuuming for 15 hours, and make the vacuum degree reach 5×10 -5 After Pa, increase the temperature to 1400 degrees, and continue vacuuming for 15 hours to make the vacuum degree reach 5×10 -5 Pa. Then, a mixed gas of argon and hydrogen was introduced, the pressure was 850 mbar, and the temperature was raised to 1600° C. for synthesis, and the synthesis time was 8 hours.

[0085] Step 2: Crystal Growth

[0086] The pretreatment temperature of the insulation material is 2300°C, and the insulation is kept for 8 hours. Pretreatment of hig...

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Abstract

The invention relates to a preparation method of a low-stress and high-purity semi-insulating SiC single crystal. The method includes the steps that synthesis of high-purity SiC powder is carried out, crystal growth is carried out with a physical vapor transport method, the concentration of shallow energy level impurities is reduced in the synthesis and crystal growth processes, a heat insulation material is subjected to high-temperature pretreatment, and boron impurities are prevented from being blended in; a silicon powder raw material and a carbon powder raw material are put into a graphite crucible with a coating for SiC synthesis; the obtained high-purity SiC powder is pretreated, seed crystals are fed, vacuumizing is carried out, high-purity argon or mixed gas of argon and hydrogen is introduced in to carry out crystal growth, then the temperature is rapidly lowered to enlarge point defects, and then the temperature is slowly lowered to the room temperature to eliminate stress. SiC crystal growth is carried out in an equilibrium state, so that the obtained crystal is small in stress, low in microtubule density and good in quality, and the resistivity on the area of the whole crystal is 108 ohm.cm or above. The method is small in preparation investment, high in safety and free of pollution.

Description

technical field [0001] The invention relates to a method for preparing a low-stress high-purity semi-insulating SiC single crystal, belonging to the technical field of single crystal growth. Background technique [0002] As a member of the third-generation wide bandgap semiconductor materials, SiC single crystal has many excellent properties such as large band gap, high thermal conductivity, and critical breakdown field strength. Based on these excellent properties, SiC is an ideal semiconductor material for high-power devices. Among them, semi-insulating SiC single crystal can be used to prepare high-power microwave devices, which can be widely used in microwave communication, airborne radar, shipborne radar and other fields. [0003] Generally, there are two ways to obtain semi-insulating SiC single crystals. One is to form deep energy levels by doping vanadium elements, so that shallow energy level impurities can be compensated to obtain semi-insulating properties. Howe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B23/00C30B29/36
CPCC30B23/00C30B29/36
Inventor 陈秀芳徐现刚彭燕胡小波
Owner SHANDONG UNIV
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