具有场板结构GaN HEMT电场分布解析模型

Electric Field Distribution Analytic Model for Field-Plated GaN HEMT

基于具有场板结构GaN HEMT器件物理和基本器件方程,导出了器件加场板前后表面电场分布和峰值电场解析模型。当场板长度LFP与绝缘层厚度tox最优时,GaN HEMT栅极边缘电场峰值可降低至未加场板时的22%;若保持峰值电场恒定,则其漏端电压可由没有场板时的50V提高到加场板后的225V,增幅高出4倍。该解析模型所导出的电场分布与国外新近发表的源于器件方程和经验公式的模拟和实验结果基本吻合,为GaN HEMT器件场板设计提供了理论依据。

In the light of physics and basic equations of GaN-based high-electron mobility transistors （HEMT） with a field-plate, an analytic model of the surface electric field distribution and peak electric field are achieved. According to our model, when the field-plate length LFP, and dielectric layer thickness tox are optimized, the peak electric field decreases to 22 % compared with the condition with no field plate. With a well designed field plate applied, the maximum drain voltage can be improved from 50 V to 225 V while the peak electric field remaining unchanged. The results obtained from the model agree with those from the numerical simulation reported recently. The conclusions afford a good theoretically guidance to the design for GaN HEMT with field plate.