Field Mapping Of Semiconductors In A State‐Of‐The‐Art Electron Microscope

Off‐axis electron holography has been used to measure the strain and the dopant fields in semiconductor specimens that have been prepared for examination by focused ion beam milling. By using the electrical and mechanical stability of the FEI Titan TEM, electron holograms have been acquired for long time periods which leads to active dopant and strain maps with excellent signal to noise ratios. We show that the position of the electrical junction can be measured in these devices specimens with a spatial resolution of 1 nm. In addition, we demonstrate that dark field electron holography and nanobeam electron diffraction can be used to quantitatively measure the strain in a range of specimens from 10‐nm‐thick SiGe layers, SiGe recessed source and drain transistors and CESL pMOS devices. In addition, the evolution of strain during the silicidation process has been observed in SiGe device specimens.