Strain mapping technique for performance improvement of strained MOSFETs with scanning transmission electron microscopy

A new approach of strain mapping is proposed with scanning transmission electron microscopy and applied to strained MOSFETs for the first time. This technique is extended to quantitative measurement with sub-nano meter spatial resolution combining with nano-beam diffraction. As a result, two-dimensional strain mapping with sub-nano meter spatial resolution is obtained and actual strain at inversion layer was determined using experimental methods without simulation. This technique will become a powerful means of improving the performance and optimizing stress design for strained MOSFETs of 45 nm node and beyond.