Effect of Low-Temperature Supercritical Fluid Process on Electrical Performance of Degraded Ni/β-Ga2O3 Schottky Barrier Diodes

doi:10.16553/j.cnki.issn1000-985x.2025.0065

Abstract

Abstract: Advanced semiconductor processes are the key technology for enhancing the electrical performance of β-Ga₂O₃-based devices and mitigating their degradation issues in service environments. Recent studies have demonstrated that low-temperature supercritical fluid process exhibits remarkable advantages in reducing interface states of semiconductor devices， repairing etching process damage， and improving device stability. In this study， low-temperature supercritical fluid （SCF） treatment was employed on Ni/β-Ga₂O₃ Schottky barrier diodes （SBDs） that has undergone degradation in air environment. The process was carried out at 130 ℃ and 20 MPa in N₂O fluid， and then the mechanism of changes in conductivity and breakdown characteristics of the degraded SBDs before and after SCF treatment were systematically investigated by current-voltage and capacitance-voltage measurements. The results demonstrate that the increase in forward saturation current density of SBDs with SCF treatment is accompanied by bulk traps reduction and series resistance decrease. Schottky barrier height elevation and depletion layer broadening effectively inhibit the electron tunneling， leading to leakage current reduction. Additionally， the study illuminates that interface state density of degraded Ni/β-Ga₂O₃ SBDs is not significantly affected by SCF treatment， and the interface traps with large time constants do not significantly affect the Schottky barrier height. This study provides critical experimental evidence and theoretical support for the application of low-temperature supercritical fluid process in optimizing the performance of β-Ga₂O₃-based devices.

Key words: low-temperature supercritical fluid process; ultrawide bandgap semiconductor; β-Ga₂O₃; Schottky barrier diode; interface state density; electrical performance

CLC Number:

TN31

SONG Yushan, CHEN Hao, LI Song, YANG Mingchao, YANG Songquan, YANG Sen, ZHOU Leidang, GENG Li, HAO Yue, OUYANG Xiaoping. Effect of Low-Temperature Supercritical Fluid Process on Electrical Performance of Degraded Ni/β-Ga₂O₃ Schottky Barrier Diodes[J]. Journal of Synthetic Crystals, 2025, 54(9): 1574-1583.

Figures/Tables 8

Fig.1 Schematic diagram of Ni/β-Ga2O3 SBDs （a） and the key process flow for device manufacturing （b）

Fig.2 Frequency-dependent C-V curves and 1/C2-V curves at reverse bias of degraded Ni/β-Ga2O3 SBDs for W/O （a）， SCF-1 h （b） and SCF-2 h （c） conditions， and high-frequency curves for the three conditions （d）

Fig.3 Extracted net carrier concentration at different frequencies from 1/C2-V curves of degraded Ni/β-Ga2O3 SBDs before and after low-temperature supercritical fluid treatment

Fig.4 Frequency-dependent Schottky barrier height obtained from the C-V curves of degraded Ni/β-Ga2O3 SBDs before and after low-temperature supercritical fluid treatment

Fig.5 Frequency-dependent C-V curves and G/-V curves at forward bias of degraded Ni/β-Ga2O3 SBDs for W/O （a）， SCF-1 h （b） and SCF-2 h （c） conditions， and interface state density as a function of the frequency （d）

Fig.6 Forward J-V curves， specific on-resistance （a）， threshold voltage， ideality factor and Schottky barrier height （b） of Ni/β-Ga2O3 SBDs under different conditions

Fig.7 Series resistance （a） and Schottky barrier height （b） of Ni/β-Ga2O3 SBDs under different conditions obtained from the Norde's method

Fig.8 Reverse J-V characteristics （a） and Fowler-Nordheim plot （b） of Ni/β-Ga2O3 SBDs under different conditions

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Effect of Low-Temperature Supercritical Fluid Process on Electrical Performance of Degraded Ni/β-Ga₂O₃ Schottky Barrier Diodes

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