An Accurate Model of RF GaN HEMTs Based on the 0.12 um Process by Using the Physics-Based ASM-HEMT Model

In this work, the characteristics of direct current and small-signals of gallium nitride on silicon carbide high electron mobility transistors (GaN/SiC HEMTs) with 0.12 um gate length are modeled using Advanced SPICE Model for HEMT (ASM-HEMT). The short channel effects of the small gate length device, such as velocity saturation effect, drain induced barrier lowering (DIBL) effect and the channel length modulation (CLM), have been studied in the physical modeling, which show that the transfer and output curves in the model fit well compared with the measured curves. Meanwhile, to study the high-order nonlinear effects of self-heating, the thermal resistance of about 27 Ω has been extracted by comparing the results between the current in pulse mode and continuous wave mode and the RC sub-circuit are also used to build the self-heating modeling. What's more, the R/L/C parameters of the external network apart from the core ASM model have been extracted to study the parasitic characteristics of devices. Hence, the complete device model with small gate length by using 0.12 um process have been obtained and the physical model accuracy is proved to be very high, which not only benefit to the precise circuit design, but also give the effective guides to develop the RF GaN HEMTs processes with smaller gate length.