Investigation of Electrical Pulse-Driven Processes by Ultrafast Tem

In the last couple of decades, significant advancements have been made in the development of ultrafast transmission electron microscopy (UTEM). It has enabled the exploration of short-lived transient stages involved in various material processes in time scales ranging from a few femtoseconds to microseconds.^1,2 In a usual UTEM setup, the sample excitation laser pulse is synchronized at a selected time delay with another laser pulse for the photoemission of electrons to probe the material dynamics. To investigate the sample excitation by other means such as electric pulses, a specialized in-situ TEM holder can be utilized in synchronization with the electron probe pulse. It opens many opportunities to investigate various material dynamics driven by electric pulses at high temporal resolution in a TEM.^3,4 Amongst many such processes, failure of electrical contacts is a major concern in the reliability of modern-day electronic devices due to exposure to extreme conditions because of miniaturization. Particularly, the failures caused by pulsed DC excitations occur extremely fast, leaving us with very limited information from post-characterization to determine the evolution of failure. In this study, we have utilized the capability of UTEM to probe the transient stages involved in the failure process via single-shot imaging. To further characterize the intermediate stages, specific experiments were performed to investigate the material morphology using a variety of electron microscopy techniques. In this presentation, we will discuss various aspects of the failure process, including time scales, the evolution of material morphology, and underlying mechanisms.<br/><br/>1. B. Barwick, H. S. Park, O.-H. Kwon, J. S. Baskin, A. H. Zewail, <i>Science</i>. <b>322</b>, 1227–1231 (2008).<br/>2. H. Doömer, O. Bostanjoglo, <i>Review of Scientific Instruments</i>. <b>74</b>, 4369–4372 (2003).<br/>3. M. Möller, J. H. Gaida, S. Schäfer, C. Ropers, <i>Commun Phys</i>. <b>3</b>, 1–7 (2020).<br/>4. X. Fu, E. Wang, Y. Zhao, A. Liu, E. Montgomery, V. J. Gokhale, J. J. Gorman, C. Jing, J. W. Lau, Y. Zhu, <i>Sci Adv</i>. <b>6</b>, 1–9 (2020).