Effect of optical phonon scattering on the performance of GaN transistors

Abstract—A model based on optical phonon scattering is developed to explain peculiarities in the current drive, transcon-ductance, and high-speed behavior of short-gate-length GaN tran-sistors. The model is able to resolve these peculiarities and provides a simple way to explain transistor behavior in any semiconductor material system in which electron–optical-phonon scattering is strong. Index Terms—fT, high-electron-mobility transistor (HEMT), optical phonons, saturation current, scattering, transconductance. I