An improved large-signal model for harmonic-balance simulation of Si LD-MOSFETs

An improved large-signal model was developed for harmonic-balance simulation of RF power Si LD-MOSFETs. The model augments the popular BSIM4 model with a voltagecontrolled voltage source to account for the nonlinear resistance of the lightly doped drain. The functional form of the voltagecontrolled voltage source is based on device physics and 2-D numerical simulation. A thermal sub-circuit is included to account for dynamic self heating. The resulted large-signal model was implemented in the popular circuit simulator ADS and found to converge readily. The model was extensively validated in terms of de and pulsed I-V characteristics, S-parameters, dynamic load lines, gain, output power, power-added efficiency, and load-pull characteristics.