Circuit simulation models for the high electron mobility transistor

A three-terminal model is formulated for the high electron mobility transistor (HEMT) using charge-voltage relationships derived from the Boltzmann transport. Emphasis is placed on modeling the current transport of the two-dimensional electron gas (TEG) and the capacitance of the embedded parasitic MESFET structure. Furthermore, a distributed circuit topology is used to better model high-frequency effects, such as the transit time delay, in both small-signal and large-signal-transient analysis. The HEMT model is implemented in the circuit simulation program HP-SPICE. Both dc and ac simulation results are discussed.