TEMPERATURE-DEPENDENCE OF CONDUCTIVITY AND HALL CARRIER CONCENTRATIONOF POLYCRYSTALLINE SIC DEPOSITED ON FUSED-SILICA BY LASER-ABLATION

The conductivity and Hall coefficient of polycrystalline SiC films dep osited on quartz are studied in the temperature ranges of 13-1275 K an d 17-800 K, respectively. Since conductivities were monotonically incr easing with the increasing temperature, these films can be used as the rmistors over the entire temperature range, While Hall mobility shows a weak temperature dependence, the electron concentration, as computed from n=1/qR(H), increases exponentially with temperature from 10(19) to 4x10(20) cm(-3). Three well-separated activation energies, computed from the measured conductivity and Hall concentration, are in the ran ges of 0.4-3.8 meV, 7-20 meV, and 55.5 +/-5 meV. Due to high electron concentration measured at temperatures as low as 17 It, impurity/defec t related conduction or thermally activated hopping may be dominant at low temperatures. (C) 1998 American Vacuum Society.