All-Oxide Transparent Vertical Indium Tin Oxide and Aluminum-Doped Zinc Oxide/-Ga₂O₃ Schottky Diodes

Herein, the fabrication and characterization of low-resistance all-oxide transparent vertical beta-Ga2O3 diodes using indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO) Schottky contacts are reported. It is shown that an ITO ohmic contact to n(+)-beta-Ga2O3 substrate is formed after annealing in N-2 at 800 degrees C. Both AZO- and ITO-based Schottky diodes show well-behaved current-voltage characteristics. Average Schottky barrier heights and ideality factors are 0.99 and 1.05eV and 0.95 and 1.03eV for AZO and ITO Schottky contacts, respectively. The on-off current ratio is about 2 x 10(10) and 1 x 10(10) for AZO and ITO Schottky contact, respectively. Moreover, the on-state resistance is about 6-7 and 4-5m Omega cm(2) for AZO and ITO Schottky contact, respectively, and is 20-35 times lower than for previously reported transparent beta-Ga2O3 Schottky diodes.