Exploring Switching Behavior of Dual-Gate RF GaN HEMTs: Characterization and Modeling

Abstract

This letter presents a comprehensive performance analysis and both linear and nonlinear modeling of dual-gate gallium nitride (GaN)-on-silicon (Si) depletion mode high electron mobility transistor (HEMT) devices across various switch topologies. We evaluate large-signal behavior to assess power handling capabilities in three configurations: series, shunt, and single-pole single-throw (SPST) at 6.5 GHz. For the SPST switch at 500 MHz, measurements reveal an on-resistance ( $R_{\text {on}}$ ) of $2.7~\Omega {\cdot }\text {mm}$ , off-capacitance ( $C_{\text {off}}$ ) of 53.3 fF, peak insertion loss (IL) of 0.6 dB, and isolation (ISO) of 53.3 dB. These metrics are also evaluated across six different peripheries, ranging from NF $\cdot $ W =400 to $6400~\mu $ m. In addition, we introduce and validate a surface potential-based modeling framework for dual-gate RF GaN HEMTs using on-wafer dc measurements, common-gate S-parameters, and large-signal measurements. Furthermore, we explore the potential single-pole-double-throw (SPDT) design by utilizing SPST switch S2P files in conjunction with model results.