Method for prolonging minority carrier lifetime of silicon carbide epitaxial material

A minority carrier and epitaxial material technology, which is applied in the field of improving the minority carrier life of silicon carbide epitaxial materials, can solve the problems of complex process and material pollution, and achieve simple process, reduce etching effect, and eliminate carbon vacancies Effect

Pending Publication Date: 2022-04-12
NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD
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Problems solved by technology

[0004] In order to solve the technical problem that the method for increasing the minority carrier lifetime of SiC epitaxial materials is complex and easily pollutes the material in the prior art, the present invention provides a method for improving the minority carrier lifetime of SiC epitaxial materials

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  • Method for prolonging minority carrier lifetime of silicon carbide epitaxial material

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Embodiment 1

[0029] Improve the minority carrier lifetime of 50 μm thick SiC epitaxial materials prepared on N-type SiC substrates (using ethylene, trichlorosilane and nitrogen as carbon source, silicon source and doping source respectively), such as figure 1 shown, including the following steps:

[0030] Step 1: Place the cleaned N-type SiC substrate into the reaction chamber of the SiC chemical vapor deposition equipment, and vacuumize the reaction chamber to a degree of 2×10 -3 mbar;

[0031] Step 2: Pass high-purity hydrogen into the reaction chamber, adjust the pressure of the reaction chamber to 80mbar, slowly increase the temperature to 1650°C, adjust the flow rates of ethylene, trichlorosilane and nitrogen to 18sccm, 75sccm and 250sccm respectively and set them as exhaust , keep the temperature for 5 minutes after the temperature stabilizes, and then perform surface treatment on the SiC substrate;

[0032] Step 3, keep the temperature and pressure of the reaction chamber constant...

Embodiment 2

[0039] Improve the minority carrier lifetime of 50 μm thick SiC epitaxial materials prepared on N-type SiC substrates, and use hydrogen chloride to assist in the treatment of the substrate surface (using ethylene, trichlorosilane and nitrogen as carbon sources, silicon sources and doping sources respectively ).

[0040] Step 1, place the cleaned SiC substrate into the reaction chamber of the SiC chemical vapor deposition equipment, and vacuumize the reaction chamber to a degree of 2×10 -3 mbar;

[0041] Step 2, feed high-purity hydrogen into the reaction chamber, adjust the pressure of the reaction chamber to 80mbar, slowly increase the temperature to 1650°C, and adjust the flow rates of ethylene, trichlorosilane, nitrogen and hydrogen chloride to 18sccm, 75sccm, 250sccm and 10sccm and set to exclude, after the temperature stabilizes, pass hydrogen chloride into the reaction chamber for 3 minutes, and perform surface treatment on the SiC substrate;

[0042] Step 3, keep the ...

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Abstract

The invention provides a method for prolonging the minority carrier lifetime of a silicon carbide epitaxial material, and the method comprises the steps: 1, placing a SiC substrate in a reaction chamber, and carrying out the vacuum pumping; 2, introducing hydrogen into the reaction chamber, and introducing a carbon source, a silicon source and a doping source for surface treatment; 3, a carbon source, a silicon source and a doping source are introduced into the reaction chamber for growth of a buffer layer; 4, epitaxial layer growth and epitaxial layer doping are carried out; step 5, first-stage cooling: closing the silicon source and the doping source, performing hydrogen atmosphere annealing treatment, and closing the carbon source after annealing is finished; 6, second-stage cooling is conducted, specifically, hydrogen atmosphere annealing treatment is conducted; seventhly, the sixth step is repeated for multiple times till the temperature requirement is met; and 8, reducing the cavity opening temperature, opening the reaction chamber, and taking out the silicon carbide epitaxial material. The method provided by the invention is simple in process and suitable for industrial production; the service life of a carrier is prolonged to the maximum extent, and damage to the surface of the material due to long-time high-temperature annealing can be avoided.

Description

technical field [0001] The invention belongs to the technical field of silicon carbide epitaxy, and in particular relates to a method for improving the lifetime of minority carriers of silicon carbide epitaxy materials. Background technique [0002] SiC material has the advantages of high thermal stability, high breakdown electric field, high thermal conductivity and good switching characteristics. It is an ideal material for preparing high-voltage and high-power devices. Areas such as DC transmission systems play a vital role. As the breakdown voltage of high-voltage and high-power devices continues to increase, the on-resistance and power consumption of devices continue to increase, and unipolar devices can no longer meet the demand. Bipolar devices can effectively reduce on-resistance through conductance modulation, so SiC bipolar devices have attracted widespread attention of researchers. To make bipolar devices realize effective electrical conduction, materials are re...

Claims

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Application Information

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IPC IPC(8): H01L21/02C30B29/36C30B25/02
Inventor 王翼李赟赵志飞周平
Owner NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD
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