Impact of Dry-Etching and Surface Repair on the Electrical Performance and Reliability of β -Ga 2 O 3 Schottky Barrier Diodes

The fabrication of advanced high-voltageβ-Ga2O3Schottky barrier diodes (SBDs) frequently relies on plasma-based dry etching techniques; however, the process introduces surface damage and interface states that degrade device performance and may also compromise the long-term reliability. This work presents a comprehensive investigation of dry-etch-induced degradation and the effectiveness of tetramethylammonium hydroxide (TMAH) treatment in repairing the etched surface. Systematic electrical characterization reveals that dry etching broadens the barrier-height distribution and enhances reverse leakage. Conversely, TMAH treatment effectively restores barrier uniformity and suppresses parasitic transport paths.On-state reliability was evaluated under various stress voltages and temperatures. The etch-treated devices exhibit the most severe performance variation, with turn-on voltage shifts exceeding 23.85% under 7-V stress and 34.56% at 400 K, together with strong leakage current escalation and the emergence of trap-assisted transport after stress. TMAH-treated devices demonstrate greatly improved stability, showing degradation trends comparable to or smaller than those of unetched SBDs. The findings demonstrate that device reliability is more sensitive to interface treatment than static electrical metrics alone suggest and highlight the necessity of post-etch repair for achieving robust Ga2O3power devices.