  It has been a widely growing interest in using silicon carbide (SiC)in
high-power electronic devices. Yet, SiC wafers may contain killer defects that
could reduce fabrication yield and make the device fall into unexpected
failures. To prevent these failures from happening, it is very important to
develop inspection tools that can detect, characterize and locate these defects
in a non-invasive way. Current inspection techniques such as Dark Field or
Bright field microscopy are effectively able to visualize most such defects;
however, there are some scenarios where the inspection becomes problematic or
almost impossible, such as when the defects are too small or have low contrast
or if the defects lie deep into the substrate. Thus, an alternative method is
needed to face these challenges. In this paper, we demonstrate the application
of coherent Fourier scatterometry (CFS) as a complementary tool in addition to
the conventional techniques to overcome different and problematic scenarios of
killer defects inspection on SiC samples. Scanning electron microscopy (SEM)has
been used to assess the same defects to validate the findings of CFS. Great
consistency has been demonstrated in the comparison between the results
obtained with CFS and SEM.
