Atomic-scale in situ TEM investigation of electron beam-induced repair of multiple defects in α -Ga2O3 heterogeneous epitaxial single-crystal films

In the process of epitaxial growth of α-Ga2O3, high density dislocations influence the quality of materials and the performance of devices. In this work, the effects of electron beam irradiation in transmission electron microscope (TEM) on different kinds of defects in α-Ga2O3 were studied. For dislocations, in situ dark field images based on different diffraction vectors and high-resolution TEM images both indicate that after electron beam irradiation (2500 e/Å2s), the repair phenomenon of dislocations with a Burgers vector of 1/3 ⟨112¯3⟩ and 1/3 ⟨11¯00⟩ is observed. With respect to larger size defects, the nano pit (8 × 5 nm2)was repaired to a large extent along (101¯4) after irradiation by an electron beam of 2500 e/Å2s for 39 min. Under electron beam irradiation with the same intensity for 42 min, the nanopore (10 × 9 nm2) was partially repaired along (0006) due to the more severe damage. This discovery provides a method to reduce the defects in two-dimensional α-Ga2O3, which is conducive to the further understanding of the properties of two-dimensional α-Ga2O3 and the development of a variety of devices based on it. At the same time, the potential impact of electron beam irradiation needs to be considered in the process of device manufacturing and the reliability of devices in space. On the contrary, this work also provides positive guidance for defect repair in other semiconductor materials that may be sensitive to electron beam irradiation.