Superior high temperature performance of 8 kV NiO/Ga2O3 vertical heterojunction rectifiers

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2023-06, Vol.11 (23), p.7750-7757
• Main Authors: Li, Jian-Sian, Chao-Ching, Chiang, Xia, Xinyi, Hsiao-Hsuan Wan, Ren, Fan, Pearton, S J
• Format: Article
• Language: English
• Subjects: Breakdown; Figure of merit; Gallium oxides; Heterojunctions; High temperature; Nickel oxides; Rectifiers; Thermal stability
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d3tc01200j

NiO/β-Ga2O3 vertical rectifiers exhibit near-temperature-independent breakdown voltages (VB) of >8 kV to 600 K. For 100 μm diameter devices, the power figure of merit (VB)2/RON, where RON is the on-state resistance, was 9.1 GW cm−2 at 300 K and 3.9 GW cm−2 at 600 K. By sharp contrast, Schottky rectifiers fabricated on the same wafers show VB of ∼1100 V at 300 K, with a negative temperature coefficient of breakdown of 2 V K−1. The corresponding figures of merit for Schottky rectifiers were 0.22 GW cm−2 at 300 K and 0.59 MW cm−2 at 600 K. The on–off ratio remained >1010 up to 600 K for heterojunction rectifiers but was 3 orders of magnitude lower over the entire temperature range for Schottky rectifiers. The power figure of merit is higher by a factor of approximately 6 than the 1-D unipolar limit of SiC. The reverse recovery times were ∼26 ± 2 ns for both types of devices and were independent of temperature. We also fabricated large area, 1 mm2 rectifiers. These exhibited VB of 4 kV at 300 K and 3.6 kV at 600 K. The results show the promise of using this transparent oxide heterojunction for high temperature, high voltage applications.