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High-temperature solid-phase synthesis method of high-purity silicon carbide powder

A high-purity silicon carbide and synthesis method technology, applied in the direction of carbon compounds, chemical instruments and methods, crystal growth, etc., can solve the problems that cannot be used for semi-insulating substrates, high conductivity, etc., to reduce intrinsic conductivity, The effect of reducing nitrogen content

Inactive Publication Date: 2012-10-03
上海上硅中试基地科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, silicon carbide grown by most techniques is generally too conductive for semi-insulating applications
In particular, the unintentionally added nitrogen concentration in SiC tends to be high enough in sublimation-grown crystals to provide sufficient conductivity to render SiC unusable for devices requiring semi-insulating substrates

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: High vacuum heat treatment combined with inert gas cleaning

[0029] (1) Take Si powder and C powder with a particle size of 200 mesh according to a molar ratio of 1:1, and their purity is greater than 4N;

[0030] (2) Put the uniformly mixed Si powder and C powder into a graphite crucible, place it in a heating synthesis furnace, and evacuate the synthesis furnace to 10 -4 Pa level, while raising the temperature to 600°C and keeping it for 5 hours;

[0031] (3) Fill the growth chamber with high-purity Ar gas to 500 Torr, keep it for 2 hours, and then evacuate it to 10 -3 Pa level, this process is repeated twice;

[0032] (4) Fill the growth chamber with high-purity argon to 1.333×10 4 Pa (that is, 100 Torr), the synthesis temperature is heated to 1800°C, the synthesis time is 10 hours, and then lowered to room temperature to obtain a high-purity SiC powder suitable for semiconductor SiC single crystal growth with a nitrogen content of 15ppm.

Embodiment 2

[0033] Example 2: High vacuum heat treatment combined with inert gas cleaning

[0034] (1) Take Si powder and C powder with a particle size of 250 mesh according to a molar ratio of 1.1:1, and their purity is greater than 4N;

[0035] (2) Put the uniformly mixed Si powder and C powder into a graphite crucible, place it in a heating synthesis furnace, and evacuate the synthesis furnace to 10 -4 Pa level, while raising the temperature to 1300°C and keeping it for 3 hours;

[0036] (3) Fill the growth chamber with high-purity Ar gas to 700 Torr, keep it for 5 hours, and then evacuate it to 10 -3 Pa level, this process is repeated 3 times;

[0037] (4) Fill the growth chamber with high-purity argon to 400Torr, heat the synthesis temperature to 2100°C, and the synthesis time is 5 hours, and then lower it to room temperature to obtain a high-purity argon gas suitable for semiconductor SiC single crystal growth with a nitrogen content of 5ppm. SiC powder.

Embodiment 3

[0038] Embodiment 3: High vacuum heat treatment combined with inert gas cleaning

[0039] (1) Take Si powder and C powder with a particle size of 60 mesh according to a molar ratio of 1.5:1, and their purity is greater than 4N;

[0040] (2) Put the uniformly mixed Si powder and C powder into a graphite crucible, place it in a heating synthesis furnace, and evacuate the synthesis furnace to 10 -4 Pa level, while raising the temperature to 1000°C and keeping it for 10 hours;

[0041] (3) Fill the growth chamber with high-purity Ar gas to 200 Torr, keep it for 10 hours, and then evacuate it to 10 -3 Pa level, this process is repeated twice;

[0042] (4) Fill the growth chamber with high-purity argon to 500Torr, heat the synthesis temperature to 2000°C, and the synthesis time is 20 hours, and then lower it to room temperature to obtain a high-purity argon gas suitable for semiconductor SiC single crystal growth with a nitrogen content of 10ppm. SiC powder.

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Abstract

The invention relates to a high-temperature solid-phase synthesis method of high-purity silicon carbide powder. The high-temperature solid-phase synthesis method comprises the following procedures of: material compounding: uniformly mixing high-purity Si powder and high-purity C powder according to the molar ratio of (1:1)-(1.5:1); high-vacuum heat treatment: placing high-purity Si and C powder into a crucible, placing the crucible in a heating furnace, vacuumizing a growth chamber of the heating furnace to be below 9*10<-4> Pa, increasing the temperature to 600-1300 DEG C and maintaining the temperature for more than 2 h; inert gas cleaning: charging a high-purity inert gas under first specified pressure into the growth chamber, maintaining for more than 1 h, vacuumizing the growth chamber to be below 9*10<-3> Pa once again, and repeating the procedure more than twice; and high-temperature synthesis: in the present of high-purity inert gas under a second specified pressure, reacting for more than 2 h at the reaction temperature of 1500-2500 DEG C, and cooling to room temperature to obtain the high-purity silicon carbide powder with nitrogen content below 15 ppm.

Description

technical field [0001] The present invention relates to the field of inorganic non-metallic materials, specifically to the technical field of silicon carbide synthesis, and in particular to a high-purity silicon carbide powder, especially a high-temperature solid-phase synthesis method for high-purity silicon carbide powder with low nitrogen content. Silicon carbide raw materials can be widely used in the growth of semiconductor SiC single crystals and the preparation of high-purity SiC ceramic samples. Background technique [0002] Silicon carbide (SiC) single crystal material has properties such as wide bandgap, high thermal conductivity, high electron saturation mobility, high breakdown electric field, etc. Compared with the first-generation semiconductor materials and the second-generation semiconductor materials, it has obvious advantages , is considered to be an ideal semiconductor material for the manufacture of optoelectronic devices, high-frequency high-power device...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/36C30B29/36C04B35/565C01B32/984
Inventor 高攀陈建军严成锋刘熙孔海宽忻隽郑燕青施尔畏
Owner 上海上硅中试基地科技有限公司
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