Barrier inhomogeneities and electrical characteristics of Ti/4H-SiC Schottky rectifiers

Forward density-voltage (J-V) measurements of titanium/4H-SiC Schottky rect ifiers are presented in a large temperature range, While some of the device s present a behavior in accordance with the thermionic current theory, othe rs present an excess forward current at low voltage level. This anomaly app ears more or less depending on the rectifier and on the temperature, A mode l based on tno parallel Schottky rectifiers with different barrier heights is presented, The whole characteristics are fitted with good agreement, It is shown that the excess current at low voltage can be explained by a lower ing of the Schottky barrier in localized regions, A proposal for the physic al origin of these low barrier height areas is given.