Strain mapping of tensiley strained silicon transistors with embedded Si1-yCy source and drain by dark-field holography

Dark-field holography, a new transmission electron microscopy technique for mapping strain distributions at the nanoscale, is used to characterize strained-silicon n-type transistors with a channel width of 65 nm. The strain in the channel region, which enhances electron mobilities, is engineered by recessed Si0.99C0.01 source and drain stressors. The strain distribution is measured across an array of five transistors over a total area of 1.6 mu m wide. The longitudinal tensile strain reaches a maximum of 0.58%+/- 0.02% under the gate oxide. Theoretical strain maps obtained by finite element method agree well with the experimental results.