Microwave properties of semi-insulating silicon carbide between 10 and 40 GHz and at cryogenic temperatures

The complex permittivity of high-purity, semi-insulating, axis-aligned monocrystalline 4H-SiC has been determined over the frequency range 10–40 GHz and at temperatures from 40 up to 295 K using whispering gallery modes and quasi TE0, n, p modes in a dielectric resonator constructed from seven layers of a 375 μm thick wafer. The real part of the permittivity (in the plane of the wafers) was found to be nearly independent of frequency. The dielectric loss tangent of 4H-SiC increases with temperature above 100 K. All results were obtained for the semiconductor in darkness.