AN ENSEMBLE MONTE-CARLO STUDY OF HIGH-FIELD TRANSPORT IN BETA-SIC

The high-field transport of electrons in beta-SiC is investigated by use of an ensemble Monte Carlo technique. We consider scattering by acoustic deformation potential, polar optical phonon, two different equivalent intervalley phonons (one first-order and one zero-order interaction), impurity scattering and impact ionization. The intervalley coupling constants and deformation potential constant are estimated by fitting the ohmic mobility to the measured experimental values over the temperature range 50-1000 K. Polar runaway occurs above 5 x 10(5) V/cm. The distribution can be partially stabilized by impact ionization processes, but the runaway is still observed. For a nonparabolic band model, the drift velocity has a gentle peak around 4 x 10(5) V/cm. The peak value is 1.9 x 10(7) cm/s, which is comparable to the experimental value observed in 6H-SiC (2.1 x 10(7) cm/s).