High-resolution elemental mapping of titanium oxide/aluminium oxide multilayer by spectrum-imaging

A spectrum-imaging technique based on scanning transmission electron microscopy combined with an electron energy-loss spectroscopy has been applied for the multilayer of amorphous titanium oxide and aluminium oxide layers on silicon substrate. We demonstrate the high-resolution elemental mapping and discuss the advantage of this method compared to an energy-filtering transmission electron microscopy. The main advantage is the absence of chromatic broadening, which allows the use of a large collection angle to acquire spectrum-image data and a wide energy window to integrate the core-loss signals. This suggests that the spatial resolution of elemental maps is mainly determined by the size of the electron probe.