High-frequency, high-power performance of AlGaN-channel high-electron-mobility transistors: An RF simulation study

Abstract

The emerging Al-rich AlGaN-channel Al x Ga1-xN/Al y Ga1-yN high-electron-mobility transistors (HEMTs) with 0.7 ≤ y < x ≤ 1.0 have the potential to greatly exceed the power handling capabilities of today's GaN HEMTs, possibly by five times. This projection is based on the expected 4× enhancement of the critical electric field, the 2× enhancement of sheet carrier density, and the parity of the electron saturation velocity for Al-rich AlGaN-channel HEMTs relative to GaN-channel HEMTs. In this paper, the expected increased RF power density in Al-rich AlGaN-channel HEMTs is calculated by theoretical analysis and computer simulations, based on existing data on long-channel AlGaN devices. It is shown that a saturated power density of 18 W mm-1, a power-added efficiency of 55% and an output third-order intercept point over 40 dB can be achieved for this technology. The method for large-signal RF performance estimation presented in this paper is generic and can be applied to other novel high-power device technologies at the early stages of development.