Application and prospect of <i>in situ</i> TEM in wide bandgap semiconductor materials and devices

Wide bandgap semiconductor (WBS) materials have a wide range of applications in radio frequency and power electronics due to their many advantages such as high saturation drift velocity, breakdown voltage, and excellent thermal/chemical stability. Diamond, Ga2O3, GaN, and SiC are typical WBS materials. Reliability studies for these four materials and devices are crucial for WBS applications. Traditional means of reliability studies include, but are not limited to, x-ray diffraction, atomic force microscopy, Raman spectroscopy, and electron microscopy et al. However, most of these methods are ex situ studies after material or device failure and thus have some limitations. In situ transmission electron microscope (TEM) is a favorable technology to observe the degradation and failure process of materials and devices in real time, which may provide effective guidance in material growth, device structure design, device process optimization, and reliability improvement. In recent years, in situ TEM technology has been gradually used by researchers to study WBS materials and devices. In this review, we present a comprehensive and systematic review of in situ TEM works on diamond, Ga2O3, GaN, and SiC materials and devices, with a particular focus on the progress of the technology in the reliability study of such materials and devices. While summarizing the advantages of in situ TEM in the investigation of WBS materials and devices, the review also looks forward to the future of in situ TEM in promoting the study of WBS materials and devices.