Development of global calibration for accurate GaAs-PHEMT simulation

Today's GaAs PHEMTs make it possible to cover applications of an extremely wide frequency range, as high as 100 GHz, with a single device type. In this paper, a set of models and calibrations for the predictive device simulation of GaAs PHEMTs is developed. The simulation setup includes a description of the device geometry. In particular, a realistic representation of the region between the ohmic contacts and the channel is included along with the fitting procedure of the simulation parameters and the necessary transport and interface models. In addition, special emphasis has been placed on a simultaneous fitting of currents and capacitances. The resulting setup allows us to describe different devices without changing any nontechnology dependent parameters and thus provides a global calibration within a given device family. This capability is demonstrated by comparing the measured and simulated results of five very different devices which cover gate lengths from 120 to 500 nm, transconductances from 400 to 800 mS/mm, and ungated channel lengths from 70 to 600 nm.