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

Due to the non-availability of p-type β-Ga₂O₃ films, p-type NiO _x is gaining attention as a promising alternative to complement the n-type β-Ga₂O₃ films. This work investigated the band-to-band tunneling (BTBT) related reverse leakage current in NiO _x /β-Ga₂O₃ PN junction diodes. The analysis reveals that a low barrier between the valence band maxima of NiO _x and conduction band minima of β-Ga₂O₃ may promote direct BTBT and trap-assisted BTBT currents during the reverse bias. On the contrary, NiO _x /β-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 NiO _x /β-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 NiO _x /β-Ga₂O₃ heterojunction diodes for future high-power applications.