Low-doped 6H-SiC n-type epilayers grown by sublimation epitaxy

Sublimation epitaxy has not yet been a technique of prime importance to gro w epitaxial 6H-SiC layers because grown layers have always shown a residual net doping level higher than 10(16) cm(-3) and a high compensation level. We present here results obtained with an optimized technology of sublimatio n epitaxial growth, which can be used to obtain structurally perfect layers with a concentration of uncompensated donors as low as 10(15) cm(-3). Thes e layers have been both physically and electrically characterized. Deep lev el transient spectroscopy indicates that the concentration of deep levels i s greatly reduced. As a consequence the hole diffusion length is significan tly increased up to about 2.5 mu m, as confirmed by electron beam induced c urrent measurements. So these optimized layers are envisaged for the fabric ation of high voltage diodes or bipolar transistors. (C) 2000 Elsevier Scie nce S.A. All rights reserved.