Practical and Reproducible Mapping of Strains in Si Devices Using Geometric Phase Analysis of Annular Dark-Field Images From Scanning Transmission Electron Microscopy

This letter reports that geometric phase analysis of high-resolution images acquired in the high-angle annular darkfield scanning transmission electron microscopy can map strains at levels of accuracy and reproducibility needed for strained-silicon-device development. Two-dimensional strain maps were reconstructed for a p-type metal-oxide-semiconductor device which was strain-engineered using a recessed source and drain. This metrology provides sufficiently practical and reproducible local-strain tensors which can be measured on a routine basis. The techniques demonstrated here are informative for process development and failure analysis in the semiconductor industry.