改进的AlGaN/GaN HEMT小信号参数提取算法

Improvement of Small Signal Modeling and Parameter Extraction for AlGaN/GaN High Electron Mobility Transistor

制作了截止频率ft和最高震荡频率fmax分别为46.2和107.8 GHz的AlGaN/GaN高电子迁移率晶体管,并针对该器件建立了包含微分电阻Rfd和Rfs在内的18元件小信号等效电路模型;在传统的冷场条件提取器件寄生参数的基础上,通过对不同栅压偏置下冷场Z参数进行线性插值运算,可消除沟道分布电阻和栅极泄漏电流对寄生电阻的影响;再利用热场S参数对寄生参数部分进行去嵌,可提取得到本征参数。分析表明,此模型和算法提高了模型拟合精度,S参数的仿真结果与测试数据在200MHz到40GHz的频率范围内均符合很好,误差不到2%。

The prototyped A1GaN/GaN high electron mobility transistor, with a cut-off frequency of 46.2 GHz,ft, and maximum oscillation frequency of 107.8 GHz,fmax, was fabricated, evaluated, modeled, and simulated. The proposed, 18-element small signal, equivalent-circuit model includes the differential resistance Rfd and Rfs. The negative impacts of the channel resistance and the gate leakage current on the parasite resistance, were eliminated by linearly interpolating the cold field Z-parameters, biased at different voltages, on the basis of the conventional cold field effect transistor. In addi- tion,the intrinsic values can be easily evaluated by de-embedding the parasitic effects with hot field S-parameters. The good agreement between the measured and the simulated results show that the newly-developed model and extraction method increase the simulation precision. For instance, at a frequency ranging from 200 MHz to 40 GHz, the differences between the simulated and the measured S-parameters were found to be less than 2%.