4H-SiC同质外延生长及Ti/4H-SiC肖特基二极管

利用台阶控制外延生长技术在偏晶向Si-面衬底上进行了4H-SiC的同质外延生长研究,衬底温度为1500℃,在厚度为32μm、载流子浓度为2～5×1015cm-3的外延材料上制备出了反向阻塞电压大于1kV的Ti/4H-SiC肖特基二极管,二极管的正向与反向电流的整流比(定义偏压为±1V时的电流比值)在室温下超过107,在265℃的温度下超过102,在20～265℃的温度范围内,利用电流电压测量研究了二极管的电学特性,室温下二极管的理想因子和势垒高度分别为1.33和0.905eV,开态电流密度在2.0V的偏压下达到150A/cm2,比开态电阻(Ron)为7.9mΩ·cm2,与温度的关系遵守Ron～T2.0规律.

Homoepitaxial Growth of 4H-SiC and Ti/4H-SiC SBDs

Homoepitaxial growth of 4H-SiC on off-oriented Si-face (0001) 4H-SiC substrates was performed at 1500℃ by using the step controlled Epitaxy. Ti/4H-SiC Schottky barrier diodes (SBDs) with blocking voltage over 1kV have been made on an undoped epilayer with 32μm in thick and 2-5 × 1015cm-3 in carrier density. The diode rectification ratio of forward to reverse (defined at ± 1 V) is over 107 at room temperature and over 102 at 538K. Their electrical characteristics were studied by the current-voltage measurements in the temperature range from 20 to 265 ℃. The ideality factor and Schottky barrier height obtained at room temperature are 1.33 and 0.905eV, respectively. The SBDs have on-state current density of 150A/cm2 at a forward voltage drop of about 2.0V. The specific on-resistance for the rectifier is found to be as 7.9mΩ·cm2 and its variation with temperature is T2.0.