Characterization of SiC crystals by optical and electrical means

Abstract

Measurements of carrier transport have been carried out in different SiC polytypes by using two complementary techniques: a picosecond four-wave mixing and magnetoresistance. Both techniques confirmed the mechanism of phonon scattering in T = 100–300 K range, as well as higher carrier mobility in n-type 4H epitaxial layers with respect to 3C-SiC. The optical technique revealed a decrease of the bipolar mobility in 3C-SiC at T < 100 K and its variation with photoexcited carrier density. A lattice heating was observed in free standing 3C- and 4H-SiC due to strong impact of nonradiative recombination, and this effect precluded optical studies of carrier dynamics at low temperatures.
Keywords: silicon carbide, carrier transport, lattice heating, transient gratings
PACS: 72.20.Jv, 78.47.+p