Energy-filtered transmission electron microscopy of multilayers in semiconductors

Knowledge about compositional profiles on an atomic scale is important for semiconductor multilayers. In this paper, we attempt to quantify the Ti atomic fraction in a TixAl1-xN multilayer and the total As concentrations in As delta-doped layers using energy-filtered imaging. These two materials represent materials where the characteristic energy loss edges are located in widely different energy losses with the L edge of Ti being above 450eV and that of As around 1350eV. The accuracy of the Ti atomic fraction in TixAl1-xN is found to be around 10at% for specimens of uniform thickness made by focused ion beam milling, whereas the resolution and As concentration for the As containing delta-layer is found to be dominated by the signal to noise ratio.