P-Type NiO Junction Termination Extension Grown by Pulsed Laser Deposition in Vertical $\beta$-Ga$_{\text{2}}$O$_{\text{3}}$ Schottky Barrier Diode

A p-type NiO junction termination extension (JTE) was incorporated into a $\beta $ -gallium oxide (Ga $_{\text{2}}$ O $_{\text{3}}$ ) Schottky barrier diode (SBD). To mitigate plasma damage on the Ga $_{\text{2}}$ O $_{\text{3}}$ surface, pulsed laser deposition (PLD) was employed for growing the NiO layer as the JTE, replacing the conventional radio frequency (RF) magnetron sputtering. Prior to the PLD process, the anode was prepared. During PLD, the substrate experienced heating, inducing an annealing effect on the device. This effect was characterized by an increase in the differential specific on-resistance ( $\textit{R}_{\text{\biosc{on},sp}}$ ) and turn-on voltage ( $\textit{V}_{\biosc{on}}$ ) based on the I–V characteristics analysis. The interface trap density also decreased from 2.65 $\times$ 10 $^{\text{12}}$ –1.76 $\times$ 10 $^{\text{12}}$ cm $^{-\text{2}}$ eV $^{-\text{1}}$ to 1.03 $\times$ 10 $^{\text{12}}$ –0.59 $\times$ 10 $^{\text{12}}$ cm $^{-\text{2}}$ eV $^{-\text{1}}$ , as demonstrated by frequency-dependent capacitance and conductance measurements, indicating an improved interface between anode and Ga $_{\text{2}}$ O $_{\text{3}}$ . The breakdown characteristics showed that the SBD with NiO-JTE achieved an improved breakdown voltage from 332 to 807 V, corresponding to a remarkable 143% increase. It is due to the fact that the NiO JTE can alleviate the electric field and reduce the peak electric field at the anode edge. The incorporation of the NiO-JTE by PLD in this study provides a valuable route to develop high performance in Ga $_{\text{2}}$ O $_{\text{3}}$ SBDs.