250. Research on the β-Ga2O3 Schottky barrier diodes with oxygen-containing plasma treatment

Fig. 1 (a) Schematics of the β-Ga2O3 SBD with plasma treatment. (b) Microscope photo of the device. (c) Region division.

Fig. 2 (a) Conductance as a function of radial frequency for conventional SBD. (b) Conductance as a function of radial frequency for SBD with N2O plasma. (c) Conductance as a function of radial frequency for SBD with O2 plasma. (d) The CV characteristics of three SBDs. (e) Trap states density and time constant as a function of their energy.

Yun-Long He, et al, Appl. Phys. Lett. 122, 163503 (2023)
https://doi.org/10.1063/5.0145659

(1) The electron affinity of GaN is 3.8eV, while β-Ga2O3 has a lower electron affinity about 3.15eV.
(2) O2 plasma can introduce oxygen ions in the anode region, which raises the barrier height.
(3) The XPS peak at 19.48eV is attributed to the Ga-N bond, which could be credited to the new component of GaN after N2O plasma treatment on the Ga2O3 surface.
(4) The N ions provided by N2O plasma can be used as donors to increase the carrier concentration of β-Ga2O3.
(5) NiOx can be formed at the interface between the anode (Ni/Au) and semiconductor (Ga2O3) generating a weak PN junction after low temperature annealing.
(6) The capacitance and conductance measurement (in the frequency range from 10 KHz to 1MHz, Agilent B1505 semiconductor parameter analyzer) indicates that the trap states energy level of the SBD without plasma treatment and with N2O and O2 plasma treatment are about 0.09, 0.084 and 0.080eV, respectively.
(7) After the N2O or O2 treatments, the deep trap states density of the SBDs reduced to form an optimized interface.