Sensitivity Analysis of Algan/Gan High Electron Mobility Transistors to Process Variation

A sensitivity analysis of AlGaN/GaN HEMT performance on material and process variations was performed. Aluminum mole fraction, barrier thickness, and gate length were varied 5% over nominal values to determine how sensitive simulated device performance was to changes in these 3 parameters. Simulated data was generated with the Synopsys TCAD software suite using a physics-based HEMT model. To validate model performance, simulated data was correlated with experimental data, which consisted of wafer epilayer characterization data as well as DC and small-signal RF device performance data from 1-26 GHz.Trends were observed in the experimental data due to variations in the fabrication process. Epilayer data showed cross-wafer trends in sheet resistance, barrier thickness and Al mole fraction but didn't show any discernable trends in mobility or sheet carrier concentration. Maximum output current was the only measured performance metric that showed a strong trend across the wafers.