GaN Transistor Designs for mm-Wave Applications

Owing to rapidly increasing demand for a higher bandwidth in the next generation communication systems, mm-waves are expected to play a critical role. Accordingly, GaN-based power amplifiers that have a high gain, output power, efficiency, and linearity at mm-wave frequencies are desired. The frequency performance of GaN HEMTs has been successfully improved through device scaling. However, a localized electric field causes current collapse, limits a breakdown voltage and maximum voltage swing, and increases a junction temperature. Abrupt pinch-off characteristics in scaled transistors degrades transistor linearity. In this talk, I will discuss technical challenges specific to mm-wave GaN transistors and our approaches to overcome existing limitations.