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 find that in contrast to the majority of the epitaxial layer, where electrically 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 1014 cm-3. A relationship between the near-surface defects and metallic impurities is suggested by a Ti concentration of I X 1016 cm-3 in this region. The high concentration of near surface defects is found to significantly reduce the carrier lifetime. © 1998 American Institute of Physics.