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 field-plate structure can significantly boost the device RF power performance, resulting in power density up to 2 W/mm measured under continuous wave RF signals at 2 GHz. The physical origin of the DC-to-RF dispersion in the fabricated devices has been associated with a hole-trap located at 0.65 eV 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.