Properties Of Heteroepitaxial 3c-SiC Films Grown by LPCVD

Abstract Polycrystalline and single-crystalline 3C silicon carbide films hetero-epitaxially grown on 3′' or 4′' Si wafers have been obtained by a hotwall type low-pressure chemical-vapour deposition (LPCVD). The internal stress of the polycrystalline film can be adjusted from 30 to 250 MPa (tensile) by changing the growth parameters, while that of the single crystal ranges from 100 to 200 MPa (tensile). The stress uniformity of the 46 mm2 polycrystalline membrane is measured to be ±9.7%, while that of the single one is ±3.0%. The biaxial Young's modulus is around 450 GPa for both the films and the burst strength for a 2.0 μm thick 20 mm2 polycrystalline membrane is about 0.4 kgf cm−2. Optical transparencies of 1.0 μm thick membranes are 70 and 80% at 633 nm for the polycrystal and the single crystal, respectively. The single crystal always shows higher transmission over the wavelength range studied and an extended absorption edge to the shorter wavelengths. The current values of mobility, carrier density and resistivity of the single crystal are roughly 180 cm2 V−1 s−1, 2 × 1018 cm−3 and 0.02 Ω cm, respectively.