Mapping the three-dimensional strain field around a microindentation on silicon using polishing and Raman spectroscopy

The strain field around a Vickers microindentation of crystalline silicon (001) has been mapped using Raman spectroscopy. The nature of the three-dimensional strain field of the microindentation was determined by comparing the parallel and crossed scattering geometries and applying the relations between the optical phonon frequency shift and strain. A surface layer (2 μm) was then removed by abrasive chemical polishing. The strain is preserved by the polishing process and information on microindentation depth is obtained. The produced maps give a good idea of the strain field after unloading. We find a quasicircular zone of plastic deformation where the strain follows a 1/r law.