$eta$-Ga2O3 MOSFETs with Nitrogen-Ion-Implanted Back-Barrier: DC Performance and Trapping Effects

摘要

β-Ga₂O₃ has captured attention in recent years for power electronics. Opportunities also exist for β-Ga₂O₃ transistors to operate as radio-frequency amplifiers. For highly-scaled devices, strong confinement of the channel is critical for mitigating short-channel effects. In this work, a depletion-mode n-channel β-Ga₂O₃ MOSFET with a back-barrier formed by implantation of deep nitrogen acceptors was demonstrated. Despite being fabricated on a conductive base material, the device delivered a drain current density of 103 mA/mm commensurate with the channel charge density and a large output current on/off ratio of 4×10^{9, both of which attested to the efficacy of back-barrier isolation. Pulsed current-voltage measurements revealed the presence of electron trapping under the gate manifested as a threshold voltage shift. The dominant charge trapping effect was mitigated instead of exacerbated by applying a large reverse gate bias - a behavior consistent with field-assisted trap emission. These results indicate a need for further process optimization to improve the speed and reliability of the device.}