Achievement of low turn-on voltage in Ga2O3 Schottky and heterojunction hybrid rectifiers using W/Au anode contact

• Published in: AIP advances 2024-09, Vol.14 (9), p.095201-095201-7
• Main Authors: Chiang, Chao-Ching, Li, Jian-Sian, Wan, Hsiao-Hsuan, Ren, Fan, Pearton, Stephen J.
• Format: Article
• Language: English
• Subjects: Electric contacts; Electric potential; Electric vehicle charging; Gallium oxides; Heterojunctions; Rectifiers; Schottky diodes; Voltage; Work functions
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/5.0227210

The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.