Investigating Reverse Low-Bias Conduction Mechanisms in Ga₂O₃ Schottky Barrier Diodes Using Pulsed Current Methods

This study presents a comparative analysis of direct current (DC) and pulsed current (PC) measurement methods applied to Ga2O3 Schottky barrier diodes (SBDs), particularly under reverse bias conditions. Significant discrepancies between the two methods are observed for Ga2O3 SBDs, while commercial Si SBDs show no noticeable differences under comparable conditions. The discrepancies are attributed to the wide bandgap characteristics of Ga2O3, which result in deeper trap levels and more pronounced charge trapping and detrapping behavior compared to Si. PC measurements of Ga2O3 SBDs reveal two distinct conduction regions: Schottky emission dominates at low reverse bias, while Fowler–Nordheim (FN) tunneling becomes the primary conduction mechanism at higher reverse bias. Time-dependent trapping effects are further investigated by varying the pulse width time (Tw). The results show that as Tw increases, the reverse current decreases and eventually saturates. This behavior highlights the influence of trapped charges, which impede the flow of subsequent electrons and reduce the overall current density. The effective Schottky barrier height determined by the Schottky emission is found to be highly sensitive to the trapped charges, while the barrier height obtained by FN tunneling remains largely unaffected. This work highlights the importance of utilizing dynamic measurement techniques, including PC, to accurately characterize the intrinsic properties of wide-band gap semiconductors like Ga2O3. In addition, the insights gained into the interplay between the Schottky emission and FN tunneling provide valuable guidance for optimizing the performance and reliability of Ga2O3-based devices in high-power and high-frequency applications.