OBIC STUDIES ON 6H-SIC SCHOTTKY RECTIFIERS WITH DIFFERENT SURFACE PRETREATMENTS

The influence of different surface treatments on the device characteri stics of Schottky rectifiers was investigated. Prior to the formation of Schottky barrier contacts the SiC surface was either thermally anne aled in hydrogen, etched using O-2 or CF4/Ar/H-2 as reactive gases or Ar sputtered. Differences in reverse current densities of several orde rs of magnitude for different surface treatments were observed. The ef fective device area was determined by the optical beam induced current (OBIC) technique. The results confirm that the effective device area is given by the area of the metal contact and the additional area of t he surface charge induced depletion layer. Our results indicate the im portance of an optimized surface treatment in order to control the qua lity and the area of the surface region for achieving optimum device p erformance. (C) 1997 Elsevier Science S.A.