4H-SiC肖特基二极管的电荷收集特性

Charge collection properties of a 4H-SiC Schottky diode

针对极端环境下耐辐照半导体核探测器的研制需求,采用耐高温、耐辐照的4H碳化硅(4H-SiC)宽禁带材料制成肖特基二极管,研究了该探测器对241 Am源α粒子的电荷收集效率。从电容-电压曲线得出该二极管外延层净掺杂数密度为1.99×1015/cm3。从正向电流-电压曲线获得该二极管肖特基势垒高度为1.66eV,理想因子为1.07,表明该探测器具备良好的热电子发射特性。在反向偏压高达700V时,该二极管未击穿,其漏电流仅为21nA,具有较高的击穿电压。在反向偏压为0～350V范围内研究了该探测器对3.5MeVα粒子电荷收集效率,在0V时为48.7%,在150V时为99.4%,表明该探测器具有良好的电荷收集特性。

A Schottky barrier diode was made using 4H-SiC wide band gap material, both radiation resistance and tempera- ture resistance of which are excellent due to its intrinsic properties. The charge collection properties of the 4H-SiC Schottky barri- er diode were investigated by irradiating the diode with alpha particles from z41 Am source. The net dopant concentration, 1.99 × 10^15/cm2 , are inferred from the capacitane-voltage curve. From the current-voltage curve, the barrier height and the ideality fac- tor are found to be 1.66 eV and 1.07, respectively, indicating the main current transportation process of the diode is thermal elec- tron emission. Under the reverse bias at 700 V, the diode has a leakage current of 21 nA, exhibiting a relatively high breakdown voltage. The charge collection properties of the diode to 3.5 MeV alpha particles were investigated at the reverse bias in the range of 0-350 V. The values of charge collection efficiency at 0 V and 150 V are 48.7% and 99.4%, respectively, indicating excellent charge collection properties of 4H-SiC Schottky diode.