Strain distribution around a NiSi ₂ /Si interface measured by convergent beam electron diffraction

The lattice strain distribution in a Si (001) substrate around NiSi ₂ island is measured using convergent beam electron diffraction (CBED) over a submicron area. Lower symmetric CBED patterns are observed near the interface, demonstrating that compressing and tensile strains are distributed around NiSi ₂ islands. The magnitude of the lattice strains, estimated by comparing the measurements with calculated CBED patterns, was found to be in the range of about 0.1 to 0.4%. Strain singularities were observed at NiSi ₂ island corners and attributed to a sum of certain stress components. This feature of the strain distribution is thought to be related to the shape and dimensions of the NiSi ₂ islands.