Beyond the AlGaN/GaN HEMT: new concepts for high-speed transistors

Solid state power amplifiers operating at mm- and sub-mm-wave frequencies are key components of numerous communication, sensors and defense systems. Nitride semiconductors have the potential to provide unprecedented levels of power at these frequencies. However, a multidimensional design and optimization is required to achieve acceptable levels of power gain and efficiency at high frequencies. In this paper we discuss some of the main challenges to increase the operating frequency of nitride transistors. New solutions are proposed to increase the electron confinement, electron velocity and access resistances of deeply scaled devices (Abstract figure) and to unleash their great potential. Scanning electron micrograph of 40 nm gate in an AlGaN/GaN high electron mobility optimized for mm-wave applications. (C) 2009 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim