High-Performance Ga 2 O 3 Diode Based on Tin Oxide Schottky Contact

A high-performance Schottky diode based on a 600- ${\mu }\text{m}$ -thick Cr-doped ${\beta }$ -Ga 2 O 3 single crystal has been fabricated using SnO x as the Schottky contact. The SnO x film was deposited in argon/oxygen mixture gas to ensure an oxygen-rich stoichiometry in Ga 2 O 3 near the Schottky interface, thus reducing oxygen deficiency-related interface state density. The SnO x film included three components: Sn, SnO, and SnO 2 , as revealed by X-ray photoelectron spectroscopy characterization. The high-quality Ga 2 O 3 single crystal grown by an edge-defined film-fed method has a carrier concentration of $1.0 \times 10^{18}$ cm $^{-3}$ and an electron mobility of ~90 cm 2 /Vs. The current density–voltage characteristics of the Schottky diode demonstrated high performance with a large barrier height of 1.19 eV, a close-to-unity ideality factor of 1.02, and a high rectification ratio beyond $10^{10}$ . The frequency-dependent capacitance and conductance analysis revealed that the maximum active interface state density is $2.46 \times 10^{12}$ eV $^{-1}$ cm $^{-2}$ at a frequency of 500 kHz.