Power and high temperature Schottky rectifiers

This thesis focuses on Schottky rectifier device physics and their application to the development of power and high temperature Schottky rectifiers. The topics covered are divided into three main areas; materials for high temperature Schottky rectifiers, device physics and structures for power Schottky rectifiers, and materials for power Schottky rectifiers. First, metal-diamond-like-nanocomposite and polysilicon SiC high temperature Schottky contacts are reported. Contacts fabricated from both materials show excellent thermal stability and near-ideal rectifying characteristics. Second, power SiC Schottky rectifiers with near-ideal forward characteristics and a breakdown voltage of 1720 V are reported. A detailed analysis of SiC Schottky rectifier reverse bias leakage current is also presented. Based on the reverse leakage current analysis, a novel rectifier structure called the dual-metal-trench (DMT) Schottky rectifier is proposed. Fabricated DMT devices are shown to have forward characteristics of a small Schottky barrier and reverse characteristics of a large Schottky barrier. Third, a brief investigation of power device figures of merit for semiconductor materials is presented and a dual-material GaInP on GaAs power device structure is propose. The GaInP on GaAs structure has a calculated figure of merit which is approximately 60 times better than Si and 4 times better than GaAs. Schottky rectifiers fabricated with the GaInP on GaAs structure are shown to have a factor of four improvement in breakdown voltage over GaAs devices. Finally, suggestions for future directions of power Schottky rectifiers are given.