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为了优化AlGaN/GaN HEMTs器件表面电场,提高击穿电压,本文首次提出了一种新型阶梯AlGaN/GaN HEMTs结构.新结构利用AlGaN/GaN异质结形成的2DEG浓度随外延AlGaN层厚度降低而减小的规律,通过减薄靠近栅边缘外延的AlGaN层,使沟道2DEG浓度分区,形成栅边缘低浓度2DEG区,低的2DEG使阶梯AlGaN交界出现新的电场峰,新电场峰的出现有效降低了栅边缘的高峰电场,优化了AlGaN/GaN HEMTs器件的表面电场分布,使器件击穿电压从传统结构的446 V,提高到新结构的640 V.为了获得与实际测试结果一致的击穿曲线,本文在GaN缓冲层中设定了一定浓度的受主型缺陷,通过仿真分析验证了国际上外延GaN缓冲层时掺入受主型离子的原因,并通过仿真分析获得了与实际测试结果一致的击穿曲线.
In order to optimize the surface electric field of AlGaN / GaN HEMTs and increase the breakdown voltage, a novel ladder AlGaN / GaN HEMTs structure is proposed for the first time.The 2DEG concentration of AlGaN / GaN heterojunction formed by the new structure decreases with the decrease of the epitaxial AlGaN layer thickness A small rule is that the low 2DEG region at the gate edge is formed by thinning the AlGaN layer epitaxially close to the gate edge and the 2DEG region at the gate edge is formed. Low 2DEG causes a new electric field peak at the interface of the stepped AlGaN layer and effectively reduces the occurrence of the new electric field peak The peak electric field at the gate edge optimizes the surface electric field distribution in the AlGaN / GaN HEMTs device, increasing the breakdown voltage of the device from 446 V in the conventional structure to 640 V in the new structure. In order to obtain the breakdown curve consistent with the actual test results In this paper, a certain concentration of acceptor defects is set in the GaN buffer layer. The reasons for the incorporation of acceptor ions in the epitaxial GaN buffer layer are verified by simulation analysis. The simulation results show that it is consistent with the actual test results Breakdown curve.