A new technique was developed to predict the unknown in-plane stress state and the magnitude of the stress components in (111) silicon wafers using micro-Raman spectroscopy. The approach is based on analyzing the combined signal from the initially degenerate peaks of theF2gmode in silicon as a function of the angle between the incident laser polarization and the polarization selected from the scattered beam using an analyzer. The peak position of the combined signal when plotted as a function of the angle was found to contain the information required to estimate the magnitude of the individual stress components in the plane-stress condition. The development of this technique is described in this paper for (111) silicon wafers. ©1997 American Institute of Physics.