STUDY OF CMOS COMPATIBLE RUTHENIUM OXIDE SCHOTTKY CONTACTS FOR ALGAN/GAN AND INALN/GAN DIODES AND HIGH MOBILITY TRANSISTORS GROWN ON SILICON (111) SUBSTRATES

Abstract

RuOx Schottky contact has been identified as a promising candidate towards realizing CMOS compatible, high thermal budget and low leakage GaN-based HEMTs for low cost, high temperature and high power applications.We have demonstrated that RuOx Schottky contact yield a lower leakage current and better thermal stability than Ni/Au counterpart in InAlN/GaN HEMTs. RuOx Schottky contact is more thermally stable, up to 800oC, compared to the latter at 600oC. It has also been found that the electrical and material characteristics of RuOx Schottky contact depend on the annealing ambient and pressure (vacuum, N2and Ar; with N2and Ar at the same pressure). Annealing pressure has been identified to play a vital role, but not ambient, in changing the material and electrical characteristics of RuOx Schottky contact. With RuOx thin film being semitransparent to optical excitation wavelengths, accurate thermal investigations underneath the gate of both AlGaN/GaN and InAlN/GaN HEMTs have been made possible by means of micro-Raman and Photoluminescence techniques. This is not achievable with conventional Ni/Au gate.