Quiescent Drain Voltage Dependence of Pulsed I-V Characteristics of GaN HEMTs: Analysis and Modeling

This paper presents an analysis on the dependence of the pulsed I-V characteristics of GaN HEMTs under varying quiescent drain voltage (V
dsq
) conditions, and a new model is developed for this behavior. It is found that three device parameters change with V
dsq
: threshold (or cut-off) voltage, and 2-DEG densities in source and drain side access regions. It is shown that these device parameters have a non-linear dependence on V
dsq
. The new model for this non-linear behavior w.r.t V
dsq
is validated with measured data for six V
dsq
's for two different GaN technologies. The developed model is also exercised for large signal microwave frequency performance yielding good agreement with measurements and indicating the importance of modeling this trap-related device parameter change with V
dsq
.