A SiC Schottky barrier diode (SBD) is provided having a substrate and two
or more epitaxial layers, including at least a thin, lightly doped N-type
top epitaxial layer, and an N-type epitaxial layer on which the topmost
epitaxial layer is disposed. Multiple epitaxial layers support the
blocking voltage of the diode, and each of the multiple epitaxial layers
supports a substantial portion of the blocking voltage. Optimization of
the thickness and dopant concentrations of at least the top two epitaxial
layers results in reduced capacitance and switching losses, while keeping
effects on forward voltage and on-resistance low. Alternatively, the SBD
includes a continuously graded N-type doped region whose doping varies
from a lighter dopant concentration at the top of the region to a heavier
dopant concentration at the bottom.