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

Abstract

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.