Characterization and Numerical Simulations of High Power Field-Plated pHEMTs

This paper presents the results obtained both by experimental measurements and numerical simulations carried out on state-of-the-art Field-Plated GaAs-based pHEMTs. The effect of field-plate length on DC and RF operation of pHEMTs will be discussed showing that the adoption of an optimal fieldplate structure can significantly boost the device RF power performance, resulting in power density up to 2W/mm measured under continuous wave RF signals at 2GHz. The physical origin of the DC-to-RF dispersion in the fabricated devices has been associated with a hole-trap located at 0.65eV from the valence band as obtained from current-DLTS measurements. The experimental results will also be supported and validated by numerical simulations. It will be shown that the beneficial effects arising from the adoption of the field-plate structure lie in its control on the trapped charge population responsible for the DC-to-RF dispersion mechanism