A kind of silicon carbide epitaxial material and preparation method thereof

Abstract

The invention provides a silicon carbide epitaxial material. The material comprises an N+ silicon carbide single crystal substrate layer, a P+ supporting layer located under the substrate, and an N- drifting layer located on the surface of the substrate. The method for preparing the material comprises the steps of (1) preparing the N+ substrate, (2) conducting chemico-mechanical polishing on the back side of the N+ substrate, (3) growing the P+ supporting layer on the back side, (4) thinning the front side of the N+ substrate, (5) conducting chemico-mechanical polishing on the front side, and (6) growing the N- drifting layer on the front side. Compared with a traditional silicon carbide epitaxial material, the silicon carbide epitaxial material has the advantages that the electrical resistivity of the P+ supporting layer is low, the uniformity of the P+ supporting layer is high, and requirements of high-voltage devices are met; meanwhile, the number of defects is small, manufacturing is easy, process repeatability is high, and industrial production is facilitated.

Description

technical field [0001] The invention relates to a semiconductor material, in particular to a silicon carbide epitaxial material and a preparation method thereof. Background technique [0002] Silicon carbide (SiC) is the third-generation semiconductor material developed after the first-generation semiconductor materials silicon and germanium and the second-band semiconductor materials gallium arsenide and indium phosphide. The band gap of silicon carbide is 2 to 3 times that of silicon and gallium arsenide, which enables semiconductor devices to work at temperatures above 500°C and has the ability to emit blue light; silicon carbide materials are higher than silicon and gallium arsenide. An order of magnitude high breakdown electric field determines the high voltage and high power performance of silicon carbide semiconductor devices; high saturated electron drift velocity and low dielectric constant determine the high frequency and high speed performance of the device; the t...

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Problems solved by technology

However, when silicon carbide crystals are grown by the traditional sublimation method, because the activation energy of 4H-SiC is too large when B-doped or Al-doped, it is difficult to achieve a level of resistivity lower than 0.5Ωcm, as high as 200Ωcm or higher, and cannot be used. To make P+ silicon carbide substrates, and thus cannot obtain epitaxial materials with N-base regions, so it is currently a technical difficulty that PT-IGBT devices cannot be realized based on SiC materials

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