RON and VTH Extraction in Hard-Switched E-mode GaN HEMTs: Impact of Passivation and Layout

In this paper we present a characterization methodology for on-wafer extraction of on-resistance and threshold voltage by means of pulsed IV, where the transition from off-state (high drain voltage, gate at zero) to measurement phase is tuned to move from soft to hard switching condition. Results demonstrate that: i) R-ON may show significant increase (with saturation) moving from soft to hard switching; ii) V-TH is strongly affected by hard switching operation; iii) improved passivation process results in lower on-resistance increase with marginal effect on the V-TH shift; iv) gate field plate length significantly impacts R-ON increase, thanks to the management of the electric field in the access region, with marginal effect on the V-TH shift.