High-Performance Ga2O3 Diode Based on Tin Oxide Schottky Contact

A high-performance Schottky diode based on a 600-μm-thick Cr-doped β-Ga
₂
O
₃
single crystal has been fabricated using SnOx 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 1.0×10
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 2.46×10
¹²
eV
^-1
cm
^-2
at a frequency of 500 kHz.