Electrical Characterization of metal SiC Schottky Barrier Diodes

Abstract

Silicon carbide is a semiconductor with attractive material properties for microelectronic newlineapplications. Interest in SiC stems from the properties which separate SiC from Si and GaAs. It newlineis known to be suitable for high power, high temperature and high frequency devices due to its newlinehigh thermal conductivity, high breakdown electric field, wide bandgap, high current densities newlineand chemical stability. However, there are still a number of factors that limit the performance of newlinedevices made on SiC. Among those the most important and critical factor is the formation of low newlineresistivity ohmic contact and high temperature stable Schottky diodes on SiC. Since the newlinesemiconductor device technology mainly relies on metal/semiconductor junctions, and Schottky newlinediode is a rectifying metal/semiconductor contact whose most important electronic parameter is newlineSchottky barrier height. Despite the fundamental importance of the Schottky barrier height, the newlinemechanisms, which control the barrier formation, are still far from being fully understood. newlineActually, Schottky barrier heights vary with the type of metal contact and also show different newlinevalue when measured using different techniques. Therefore, the purpose of this thesis is to newlinedetermine the influence on the Schottky barrier of various structural and electronic parameters of the junctions and explore the mechanism which can be used to modify the barrier heights. newline newlineIn this work Schottky diodes of Pt, Au, Ni, Cr, Ti and Nichrome on n-type Si faced 4H-SiC were newlinefabricated and analysed. The Schottky diodes were electrically characterized using Current- newlineVoltage (I-V) and Capacitance Voltage (C-V) measurement techniques to extract Schottky newlinebarrier height, ideality factor and substrate doping density. The barrier heights determined by I-V newlinemeasurements were found to be 1.07, 1.01, 0.92, 1.03, 0.85 and 0.79 eV for Pt, Au, Ni, Cr, Ti newlineand Nichrome/ 4H-SiC samples respectively.