4H-SiC TSOB结势垒肖特基二极管的结构优化设计

Optimal Design of 4H-SiC TSOB Junction Barrier Schottky Diodes

室温下,沟槽底部有氧化物间隔的结势垒肖特基二极管的击穿电压达到2 009V,正向导通压降为2.5V,在正向偏压为5V时,正向电流密度为300A/cm2。在P型多晶硅掺杂的有源区生成双层SiO2间隔,以优化漂移区电场分布,正向导通压降为2.5V,击穿电压达到2 230V,耐压值提高11%。反向电压为1 000V时,反向漏电流密度比普通结构降低90%,有效地降低了器件的漏电功耗。普通结构的开/关电流比为2.56×103（1~500V）,而改进结构的开/关电流比为3.59×104（1~500V）。

Trench type Schottky rectifier with oxide mass in trench bottom（TSOB）was simulated.The breakdown voltage of TSOB was 2 009Vand the forward voltage drop was 2.5Vat 300K.In order to improve reverse characteristics of the device,oxide mass was injected into the trench of TSOB.The improved structure had a breakdown voltage of 2 230Vat 2.5Vforward voltage drop,which was about 11% higher than that of TSOB, and its reverse current density was reduced by 90%,compared to TSOB without sacrificing forward voltage drop at reverse bias of 1 000V.In addition,the optimized structure had an on/off current ratios of 3.59×104（1~500V）, compared with 2.56×103（1~500V）for TSOB.