Method for forming silicon carbide polycrystalline film and method for manufacturing silicon carbide polycrystalline substrate

Abstract

To provide a deposition method for a silicon carbide polycrystalline film and a production method for a silicon carbide polycrystalline substrate, wherein: an SiC polycrystalline film is deposited by CVD with a nitrogen doping gas on a carbon support substrate, and the SiC polycrystalline film is separated from the carbon support substrate with reduced warpage, thereby solving the problem of worsened yield, cost, productivity in the process and production of an SiC polycrystalline substrate, resulting in a high-conductivity SiC polycrystalline substrate with reduced warpage.SOLUTION: A deposition method for a silicon carbide polycrystalline film includes a deposition step in which the CVD is used to, with a nitrogen gas, silicon gas, and carbon gas, deposit a silicon carbide polycrystalline film of 300 μm-1200 μm thick on a carbon support substrate of 300 μm-10 mm thick. The carbon support substrate satisfies αv / αp=2.5-4.0 where αp is a thermal expansion coefficient in a direction parallel with the thickness direction and αv is a thermal expansion coefficient in a direction orthogonal to the thickness direction.SELECTED DRAWING: Figure 1

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