Circuit simulation models for the high electron mobility

Two charge-based circuit simulation models are presented for the HEMT. One is somewhat empirically based and is termed the semiempirical model whereas the other is based on the device physics and is called the semiphysical model. Both models have been installed in the SPICE-like circuit simulation program iSMILE. In the semiempirical model, an analytical term is introduced to describe the mobility vs. gate voltage variation. Also included in this model is a method of partitioning the channel charge. The semiphysical model incorporates an analytical term for describing the gate-to-channel potential vs. channel charge characteristic. In addition, equations are presented for modeling device parasitics and the voltage-dependent fringe capacitances of the gate. Both models are shown to be more numerically efficient and more accurate than previous capacitance-based models.<>