OBSERVATION OF NEAR-SURFACE ELECTRICALLY ACTIVE DEFECTS IN N-TYPE 6H-SIC

In n-type 6H-SiC epitaxial layers grown by vapor phase epitaxy, we fin d that in contrast to the majority of the epitaxial layer, where elect rically active defects are observed with a concentration less than 1 X 10(-13) cm(-3), a region near the front surface contains defects with concentrations approaching 10(14) cm(-3). A relationship between the near-surface defects and metallic impurities is suggested by a Ti conc entration of 1 X 10(16) cm(-3) in this region. The high concentration of near surface defects is found to significantly reduce the carrier l ifetime. (C) 1998 American Institute of Physics. [S0021-8979(98)03007- 2].