With increased doping on the semiconductor, the width on the depletion location drops. Underneath a certain width, the demand carriers can tunnel from the depletion location. At pretty large doping ranges, the junction isn't going to behave as a rectifier any more and gets an ohmic contact. This may be http://sicsbd40372.suomiblog.com/not-known-details-about-sic-schottky-diodes-27495813