Influence of High-Energy Proton Irradiation on β-Ga2O3 Nanobelt Field-Effect Transistors

The robust radiation resistance of wide-band gap materials is advantageous for space applications, where the high-energy particle irradiation deteriorates the performance of electronic devices. We report on the effects of proton irradiation of β-Ga₂O₃ nanobelts, whose energy band gap is ∼4.85 eV at room temperature. Back-gated field-effect transistor (FET) based on exfoliated quasi-two-dimensional β-Ga₂O₃ nanobelts were exposed to a 10 MeV proton beam. The proton-dose- and time-dependent characteristics of the radiation-damaged FETs were systematically analyzed. A 73% decrease in the field-effect mobility and a positive shift of the threshold voltage were observed after proton irradiation at a fluence of 2 × 10¹⁵ cm^-2. Greater radiation-induced degradation occurs in the conductive channel of the β-Ga₂O₃ nanobelt than at the contact between the metal and β-Ga₂O₃. The on/off ratio of the exfoliated β-Ga₂O₃ FETs was maintained even after proton doses up to 2 × 10¹⁵ cm^-2. The radiation-induced damage in the β-Ga₂O₃-based FETs was significantly recovered after rapid thermal annealing at 500 °C. The outstanding radiation durability of β-Ga₂O₃ renders it a promising building block for space applications.