Effect of gate recessing on linearity characteristics of AlGaN/GaN HEMTs

GaN-based HEMTs are the most promising device in order to meet the requirements of new generation communication systems. In this work, devices with planar (unrecessed) and gate recessed structures have been fabricated on the same wafer, and characterized by means of RF two-tone measurements at 10 GHz. For GaAs-based devices, increasing device transconductance by means of gate recessing proved to be very effective, resulting in an overall improvement of both large and small signal performance, especially their linearity characteristics. Further optimization of gate recessing may result in higher efficiency operation while maintaining low distortion level.