Patent ID: 8585821

Claim:
A method for producing a monocrystal SiC epitaxial substrate, the monocrystal SiC epitaxial substrate including: a monocrystal SiC substrate; a buffer layer made of a first SiC epitaxial film formed on the monocrystal SiC substrate; and an active layer made of a second SiC epitaxial film formed on the buffer layer, the method comprising: a first film forming step for forming the first SiC epitaxial film by heat-treating a set of (i) the monocrystal SiC substrate, (ii) a carbon source plate, and (iii) a metal Si melt layer having a predetermined thickness and interposed between the monocrystal SiC substrate and the carbon source plate, so as to epitaxially grow monocrystal SiC; and a second film forming step for forming the second SiC epitaxial film by epitaxially growing monocrystal SiC on the first epitaxial film by vapor phase growth method, wherein: the first film forming step includes: a temperature-increasing step for increasing a temperature of the metal Si melt layer to a predetermined growth temperature set to a temperature not lower than a melting point of Si; and a temperature-decreasing step for decreasing the temperature of the metal Si melt layer from the predetermined growth temperature to a temperature not higher than 500° C.; the temperature of the metal Si melt layer is changed at least from the melting point of Si to the growth temperature at a rate of 20° C. or less per minute during the temperature-increasing step; and the temperature of the metal Si melt layer is changed at the rate of 20° C. or less per minute during the temperature-decreasing step.