Thermal stability of swift heavy ion tracks in <i>β</i>-Ga2O3 annealed at high temperatures

As an ultra-wide bandgap (∼4.8 eV) semiconductor, β-Ga2O3 is promising for applications in harsh environments. It is extremely resistant to low-energy ions, but is quite susceptible to swift heavy ions (SHIs), e.g., a single SHI can create an amorphous ion track with several nanometers in diameter. The ultra-wide bandgap allows β-Ga2O3-based devices to operate inherently at high temperatures, which facilitates defect recovery in the material. This study investigates the thermal stability of SHI tracks in β-Ga2O3 within the temperature range of 473–773 K using ex situ transmission electron and atomic force microscopy. It was found that the average diameter and morphology of tracks annealed at 673 K or above undergo a significant change due to recrystallization. Annealing at 773 K reduces the areal track density to approximately 50%. The activation energy for thermal recovery was determined to be 0.27 ± 0.03 eV. These findings provide valuable information for assessing the reliability of β-Ga2O3-based devices intended for operation in harsh environments.