Low voltage FE-STEM for characterization of state-of-the-art silicon SRAM

Low voltage (30 kV) field emission scanning transmission electron microscopy (FE-STEM) has been employed in the characterization of state-of-the-art semiconductor static random access memory (SRAM) using specimens prepared at several different thicknesses (70-180 nm). A focused ion beam (FIB) system, a FIB-SEM compatible specimen holder and an in-lens FE-SEM have been employed for alternating between FIB milling and SEM/ STEM imaging. As a result, ion implanted atom damage during manufacturing, grains in aluminium interconnects, poly silicon gates, thin metal barriers and a thin gate oxide layer were observed by low voltage FE-STEM. STEM, in-lens FESEM, FIB