On band-to-band tunneling and field management in NiOx/β-Ga2O3 PN junction and PiN diodes

Abstract Due to the non-availability of p-type β -Ga 2 O 3 films, p-type NiO x is gaining attention as a promising alternative to complement the n-type β -Ga 2 O 3 films. This work investigated the band-to-band tunneling (BTBT) related reverse leakage current in NiO x / β -Ga 2 O 3 PN junction diodes. The analysis reveals that a low barrier between the valence band maxima of NiO x and conduction band minima of β -Ga 2 O 3 may promote direct BTBT and trap-assisted BTBT currents during the reverse bias. On the contrary, NiO x / β -Ga 2 O 3 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 NiO x / β -Ga 2 O 3 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 NiO x / β -Ga 2 O 3 heterojunction diodes for future high-power applications.