Investigating the Rapid Failure of Focused Ion Beam Deposited Electrical Contacts: An In-Situ and Ultrafast Transmission Electron Microscopy Approach

Abstract

Ultrafast transmission electron microscopy (UTEM) is a valuable tool for investigating the intermediate stages of fast dynamic material processes. Here, we utilized single-shot imaging in UTEM to reveal the short-lived transient stages involved in the pulsed electrical failure of focused ion beam (FIB) fabricated platinum contacts. Particularly, the failure occurring in the halo region formed due to the broadening of the metal deposits during FIB deposition was investigated. The failure was initiated rapidly, in less than 100 ns, upon the application of a voltage pulse. These transient stages were generated for further characterization by applying voltage pulses of varying pulse widths in a conventional TEM. We identified different stages in the failure, leading to the decomposition of the substrate underneath the deposition. Simulations were performed in COMSOL Multiphysics to estimate the temperature increase resulting from Joule heating. Furthermore, various mechanisms triggered at different times leading to complete failure are discussed.