Examination of hot carrier effects of the AlGaAs/InGaAs pHEMT through device simulation

Abstract

A unified study on the hot carrier reliability and the effect of temperature on the pseudomorphic high electron mobility transistor (pHEMT) is carried out through device simulation and physical analyses. Device cross sections are evaluated at various biasings to examine the physical behavior. An accelerated DC stress regime and normal operation regime are examined through TCAD. Output characteristics are shown along with stress mechanisms within the device. This includes impact ionization, hole and electron currents, and heating effects. While these effects have been reported previously, this work provides them in a complete visual and concise manner.Lastly, a means of simulating a pHEMT post-stress is introduced. This approach accounts for the activation of dopants near the channel. Post-stress simulation results of DC and RF performance parameters (IDS, gm fT, fmax, S21) are then investigated. Simulation shows that the effect of stress is highly dependent on the chosen bias point used after stress.