4H-SiC TSOB结势垒肖特基二极管静态特性

为增强器件的反向耐压能力,降低器件的漏电功耗,采用Silvaco TCAD对沟槽底部具有SiO₂间隔的结势垒肖特基二极管(TSOB)的器件特性进行了仿真研究。通过优化参数来改善导通压降(V_F)-反向漏电流(I_R)和击穿电压的折衷关系。室温下,沟槽深度为2.2 μm时,器件的击穿电压达到1 610 V。正向导通压降为2.1 V,在V_F=3 V时正向电流密度为199 A/cm²。为进一步改善器件的反向阻断特性,在P型多晶硅掺杂的有源区生成一层SiO₂来优化漂移区电场分布,此时改善的器件结构在维持正向导通压降2.1 V的前提下,击穿电压达到1 821 V,增加了13%。在1 000 V反向偏置电压下,反向漏电流密度比普通结构降低了87%,有效降低了器件的漏电功耗。普通器件结构的开/关电流比为2.6×10³(1 V/-500 V),而改善的结构为1.3×10⁴(1 V/-500 V)。

Study on the Static Characteristics of 4H-SiC TSOB Junction Barrier Schottky Rectifiers

Trench type schottky rectifier with oxide mass in trench bottom (TSOB) is simulated with Silvaco TCAD to enhance the reverse blocking capability and leakage current power.For improving the forward voltage drop (VF)-reverse current density (IR) trade-off and the breakdown voltage are simulated and optimized.The breakdown voltage of TSOB is 1 610 V and the forward voltage drop is 2.1 V at 300K.In order to improve the device characteristics,oxide mass is injected into the trench of TSOB.The breakdown voltage is 1 821 V,which is about 13% more than that of the TSOB.The reverse current density is reduced by 87% compared to the TSOB without sacrificing the forward voltage drop at reverse bias of 1 000 V.In addition,the optimized structure has a on/off current ratio of 1.3×10⁴ (1 V/-500 V),whereas the TSOB exhibits a ratio of 2.6×10³ (1 V/-500 V).