The Trends of In Situ Focused Ion Beam Technology: Toward Preparing Transmission Electron Microscopy Lamella and Devices at the Atomic Scale

The increased complexity and scaling down of electronic devices lead to great challenges in extracting an interesting nanoscale area of the device for transmission electron microscopy (TEM) characterization. The traditional TEM sample preparation methods, such as electrolytic polishing, can not precisely process a specific area of the device. Focused ion beam (FIB) technology is an advanced in situ specimen preparation method for TEM. FIB can not only locate specific position and mill a TEM sample with the nanoscale resolution, but also manipulate the sample in a controlled manner in real time. With the development of electronic devices, variations, and optimizations of the FIB method for advanced devices with new structures have been reported. In this review, the TEM sample preparation methods for fin field-effect transistor, high electron mobility transistor, enhanced dynamic random-access memory, and 2D material-based devices are discussed. Their advantages, disadvantages, and an overview of the applications are summarized. Based on current research, future research directions for enhancing the quality of TEM samples are suggested.