AlGaN/GaN HEMT中电场分布的ATLAS模拟

ATLAS Simulation on Electrical Field Distribution of AlGaN/GaN HEMT

用Silvaco的ATLAS软件模拟了栅场板参数对AlGaN/GaN HEMT中电场分布的影响。模拟结果表明,场板的加入改变了器件中电势的分布情况,降低了栅边缘处的电场峰值,改善了器件的击穿特性;场板长度(LFP,length of field plate)、场板与势垒层间的介质层厚度t等对电场的分布影响很大。随着LFP的增大、t的减小,栅边缘处的电场峰值Epeak1明显下降,对提高器件的耐压非常有利。通过对相同器件结构处于不同漏压下的情况进行模拟,发现当器件处于高压下时,场板的分压作用更加明显,说明场板结构更适合于制备用作电力开关器件的高击穿电压AlGaN/GaN HEMT。

The electrical field distribution of AlGaN/GaN HEMT was simulated by ATLAS of Silvaco with variable parameters of gate-connected field plate （FP）. Simulation results show that the potential distribution is changed, the peak of electrical field at the edge of gate close to drain side is decreased, and the breakdown characteristic is improved by the addition of FP. Field plate length （LFp） and dielectric film thickness （t） between the field plate and barrier layer has a great influence on the electrical field distribution. Peak of electrical field at the edge of gate close to drain side is relaxed by lengthening L^p and thinning t, which is helpful to improve breakdown voltage. Simulation results of a same device under different drain-source voltage （V^s） show that the influence of field plate becomes more obviously while drain-source voltage is increased, which means that field plate is the suitable structure in the fabrication of high breakdown voltage A1GaN/GaN HEMT for power switching device.