| 摘要 |
PROBLEM TO BE SOLVED: To reduce the warping of a semiconductor substrate having an epitaxial layer by forming grooves on the surface of the epitaxial layer and carrying out heat-treating to correct the substrate from warping. SOLUTION: Grooves 4 of 30μm wide, 5μm deep are cut into the surface of an SiC substrate by the photolithography in the orientations <11-00> and <112-0> in a shape of a grid with spacings of 5mm. Then the substrate is set in a heater to heat-treat it in an Ar atmosphere at 1500 deg.C for 10min to relax the internal stress caused at the time of forming of epitaxial layers 2, 3, and the grooves serve for correcting the warping of the substrate. After correction of the SiC substrate, a MOSFET is formed as a semiconductor element on this substrate.
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