Raman spectroscopy for a micrometric and tensorial analysis of stress in silicon

This letter presents a method to measure stress by a Raman spectroscopic technique that combines high spatial resolution with tensorial analysis. The experiment is based on separating the contributions to the Raman spectrum from the marginal and paraxial rays of the collection cone of the objective. The stress tensor was measured over a 20 μm line scan with a resolution of 1 μm on a highly strained (001) silicon surface in proximity to a micrometric scratch by observing the different frequency shifts of three orthogonal crystal vibrations.