Enhanced heterostructure field effect transistor CAD model suitable for simulation of mixed mode circuits

We describe a new enhanced model for deep submicron heterostructure field e ffect transistors (HFET's) suitable for implementation in computer aided de sign (CAD) software packages such as SPICE. The model accurately reproduces both above-threshold and subthreshold characteristics of both nand p-chann el deep submicron HFET's over the temperature range 250-450 K, The current- voltage (I-V) characteristics are described by a single, continuous, analyt ical expression for all regimes of operation, thereby improving convergence . The physics-based model includes effects such as velocity saturation in t he channel, drain-induced barrier lowering (DIBL), finite output conductanc e in saturation, frequency dispersion, and temperature dependence, The outp ut resistance and the transconductance are accurately reproduced, making th e model suitable for simulation of mixed mode (digital/analog) circuits. Th e model has been extensively verified against experimental data for two HFE T technologies with gate lengths down to 0.3 mu m.