Cathodoluminescence (CL) microscopy and
spectroscopy have been used to
investigate the nature and spatial distribution
of defects and impurities in
n-type epitaxial 4H-SiC. CL microscopy reveals the existence of 6H-SiC
polytype inclusions, while CL spectra recorded at different excitation
conditions show luminescence emission related to deep levels in the SiC
epilayer. Deconvolution of the mentioned spectra indicates the complex
character of the deep-level CL emission, that is actually composed of four
bands centred near 2.72, 2.56, 2.42 and 2.00 eV at 88 K. The origin
of these bands is discussed considering previous deep level transient
spectroscopy measurements carried out in the same material investigated in
the present work.