A Surface-Potential-Based Compact Model for Study of Non-Linearities in AlGaAs/GaAs HEMTs

Abstract

We present a continuous surface-potential- based electro-thermal compact model suitable for the study of intermodulation distortion IMD in GaAs HEMT devices. We have developed a precise analytical calculation for the position of the Fermi level Ef in these devices from a consistent solution of Schrödinger's and Poisson's equations. The accuracy of our calculation is of the order of pico-volts. Ef is used to define the surface-potential ψ and subsequently derive the drain current Id. We use the developed Id model for prediction of IMD in these devices using Volterra series method. The model is in excellent agreement with experimental IMD data. The impact of various real device effects like self- heating, mobility degradation etc., on the non- linear behavior of the device is analyzed using the model.