Transmission electron microscope sample shape optimization for energy dispersive X-ray spectroscopy using the focused ion beam technique

By utilizing the focused ion beam (FIB) technique, we evaluated signal intensity ratios of analyzed areas and the matrix for energy dispersive X-ray spectroscopy with a transmission electron microscope (TEM-EDX). In the case of conventional FIB samples (H-shape), electrons scattered from the thin film area irradiate the sidewalls of the matrix (Si substrate) under the thin film position and they generate a large number of X-rays. These matrix signals are reduced by making samples as U-shaped and removing the underlying sidewalls. The final matrix (Si) X-ray signal is reduced by 90% compared with the conventional H-shaped samples.