Annealing-free Ohmic contact of β-Ga2O3via nitrogen plasma treatment†

With the advent of the artificial intelligence era, semiconductor materials with exceptional performance are increasingly in demand. Beta-gallium oxide (β-Ga₂O₃) is a promising candidate for advanced semiconductor applications; however, its limited contact performance between metal electrodes remains a critical restriction that impedes its full utilization. In this study, high-quality Ohmic contacts were established through a direct nitrogen plasma treatment, effectively preserving the crystallinity of β-Ga₂O₃ while enhancing its electrical performance. The carrier mobility of β-Ga₂O₃ reached levels up to 76 cm² V⁻¹ s⁻¹, approximately four times greater than the previously reported ranges (15–20 cm² V⁻¹ s⁻¹). The significantly improved on/off ratio (1.7 × 10¹⁰) can suppress the device malfunction due to leakage current and resolve existing structural limitations. The results of our investigation provide insights for the advancement of β-Ga₂O₃ as a cutting-edge semiconductor material for ultra-low-scale and multi-output integrated circuits.