Electrical characterization of Schottky diodes fabricated on SiC epitaxial layers grown on porous SiC substrates

Electrical characteristics of Schottky barriers fabricated on a 4H–SiC n-layer grown by chemical vapor deposition (CVD) on both porous and conventional SiC substrates were investigated. Schottky barriers were formed by thermal vacuum evaporation of nickel. Current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the barrier were measured in the temperature range from 250 to 500 K and at different frequencies, respectively. Analysis of I–V characteristics showed that the forward current might be described by classic thermal emission theory. The ideality factor of the I–V characteristics was found to be independent of temperature and to be 1.05±0.02 which is close to the ideal value. The ideality factor for the control diodes was found to be 1.13±0.02. The barrier height was extracted from I–V characteristics to be 1.45 eV for both diodes. Analysis of the C–V characteristics indicates the existence of acceptor-like surface states in the CVD n-layer grown on porous substrate and donor-like states for the control material. The comparative study of the Schottky diodes fabricated on n-layer grown on porous and conventional substrate was performed.