PtOx Schottky Contacts on Degenerately Doped \(\left( {\overline{2}01} \right)\) β-Ga2O3 Substrates

Abstract

Platinum oxide (PtO_x) Schottky contacts on degenerately doped β-Ga₂O₃ substrates show an increased barrier height of 85% and 64% when compared to nickel and platinum Schottky contacts, respectively. At low reverse voltage bias, the reverse leakage current of the PtO_x Schottky barrier diodes was approximately 5–6 orders of magnitude lower than the reference evaporated Ni and Pt Schottky contacts. PtO_x Schottky contacts were deposited using reactive sputtering on highly doped (8 × 10¹⁸ cm⁻³) (\(\overline{2}01\)) β-Ga₂O₃:Sn substrates grown by the edge-defined film-fed growth (EFG) method. All Schottky metals were capped with evaporated Au. Capacitance–voltage and temperature-dependent current–voltage measurements were performed in order to extract the barrier height of the PtO_x Schottky contact. Analysis of the diode ideality factors reveal that the PtO_x Schottky contacts on highly doped β-Ga₂O₃ do not follow the thermionic field emission model and are impacted by inhomogeneous barrier height distribution. This work highlights the significance of PtO_x Schottky contacts for β-Ga₂O₃-based power devices as a means for reducing leakage current. This work also holds relevance for low-voltage applications, where Schottky contacts for degenerately doped semiconductors can enable new electronic device applications.