High-Performance Ga₂O₃ Diode Based on Tin Oxide Schottky Contact

Abstract

A high-performance Schottky diode based on a 600-μm-thick Cr-doped β-Ga2O3 single crystal has been fabricated using SnOx as the Schottky contact. The SnOx film was deposited in argon/oxygen mixture gas to ensure an oxygen-rich stoichiometry in Ga2O3 near the Schottky interface, thus reducing oxygen deficiency related interface state density. The SnOx film included three components: Sn, SnO, and SnO2, as revealed by X-ray photoelectron spectroscopy characterization. The high quality Ga2O3 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. Current density-voltage characteristics of the Schottky diode demonstrated high performance with a large barrier height of 1.17 eV, a close-to-unity ideality factor of 1.02, and a high rectification ratio beyond 10 10. Frequency-dependent capacitance and conductance analysis revealed that the maximum active interface state density is 5.92 × 10 13 at a frequency of 7 kHz.

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

“…161 100) single crystal β-Ga 2 O 3 using long-throw reactive sputtering (LT-RS) in an argon/oxygen mixture to ensure oxygen-rich ambient conditions near the Schottky/Ga 2 O 3 surface, which reduced the oxygen-deficiency related interface defect states. 218 The SnO x /β-Ga 2 O 3 SBD exhibited a large SBH of 1.19 eV and an ideality factor of 1.02 with a high rectification ratio of about 10 10 . Such high performance of the SBD was attributed to the fact that the SnO x films mainly contained three components, Sn, SnO, and SnO 2 , revealed by X-ray photoelectron spectroscopy.…”

“…Du et al fabricated tin oxide (SnO x ) SCs on EFG grown (100) single crystal β-Ga 2 O 3 using long-throw reactive sputtering (LT-RS) in an argon/oxygen mixture to ensure oxygen-rich ambient conditions near the Schottky/Ga 2 O 3 surface, which reduced the oxygen-deficiency related interface defect states . The SnO x /β-Ga 2 O 3 SBD exhibited a large SBH of 1.19 eV and an ideality factor of 1.02 with a high rectification ratio of about 10 10 .…”

“…The main component SnO in the SnO x film was found to have a high density of tin vacancy defect states. Such tin vacancies provided oxygen dangling bonds, which compensated for the oxygen vacancies in the MS interface at β-Ga 2 O 3 …”

“…Such tin vacancies provided oxygen dangling bonds, which compensated for the oxygen vacancies in the MS interface at β-Ga 2 O 3 . 218 In an extensive study of metal oxide SCs on β-Ga 2 O 3, Hou et al demonstrated that in situ oxidation of β-Ga 2 O 3 SCs with metals can produce improved SBDs comparable to those achieved with n-type transparent conducting oxides (TCOs) such as ZnO, SnO 2 , In 2 O 3 , and CdO contacts. 212,219−221 They fabricated both pure metal and oxidized metal SCs using Ir, Pd, Pt, Ag, and Au on EFG grown (2̅ 01) as well as (010) single crystal substrate by rf sputtering under inert and oxidizing plasma conditions.…”

Enhancement Mode Ga2O3 Field Effect Transistor with Local Thinning Channel Layer

“…Epitaxial β−Ga 2 O 3 layers have been grown by many techniques including metal−organic chemical vapor deposition, molecular beam epitaxy, and pulsed laser deposition [7,8]. Ga 2 O 3 −based field−effect transistors [9][10][11], metal−semiconductor field−effect transistors [6,12], and Schottky barrier diodes [13][14][15][16] have demonstrated potential as next−generation high−power electronic devices. In particular, Ga 2 O 3 −based FETs have shown high current densities [17,18], high voltage breakdown [19], low ohmic contact resistance [20], and early prospects for modulation doping [21] and integration [22].…”