Enhanced Heterostructure Field Effect Transistor CAD Model Suitable for Simulation of Mixwd Mode Circuits

We describe a new enhanced model for deep submicron Heterostructure F ield Effect Transistors (HFETs) suitable for implementation in Comput er Aided Design (CAD) software packages such as SPICE. The model acc urately reproduces both above-threshold and subthreshold characterist ics of both n- and p-channel deep submicron HFETs over the temperatur e range 250-450 K. The current-voltage characteristics are described by a single, continuous, analytical expression for all regimes of op eration, thereby improving convergence. The physics-based model incl udes effects such as velocity saturation in the channel, drain induce d barrier lowering, finite output conductance in saturation, frequenc y dispersion, and temperature dependence. The output resistance and the transconductance are accurately reproduced, making the model suit able for simulation of mixed mode (digital/analog) circuits. The mod el has been extensively verified against experimental data for two HF ET technologies with gate lengths down to 0.3 micrometer.