On Band-to-band Tunneling and Field Management in NiOx/β-Ga2O3 PN Junction and PiN Diodes

Due to the non-availability of p-type ss-Ga2O3 films, p-type NiOx is gaining attention as a promising alternative to complement the n-type ss-Ga2O3 films. This work investigated the band-to-band tunneling (BTBT) related reverse leakage current in NiOx/ss-Ga2O3 PN junction diodes. The analysis reveals that a low barrier between the valence band maxima of NiOx and conduction band minima of ss-Ga2O3 may promote direct BTBT and trap-assisted BTBT currents during the reverse bias. On the contrary, NiOx/ss-Ga2O3 diodes in PiN configuration offer a wider BTBT depletion width and lower peak electric field, lowering the reverse leakage current by orders of magnitude. Thus, we show that NiOx/ss-Ga2O3 heterojunction diodes in PiN configuration offer better field management strategies and suppression of the reverse leakage. The analysis performed in this work is thought to be valuable in informing device-design of NiOx/ss-Ga2O3 heterojunction diodes for future high-power applications.