MAPPING OF RESIDUAL-STRESSES AROUND AN INDENTATION IN BETA-SI3N4 USING RAMAN-SPECTROSCOPY

The stress dependence of the Raman bands of silicon nitride (beta-Si3N 4) have been investigated and applied to indentation experiments. Seve n high-frequency bands have been found to have linear and negative str ess dependencies. On the other hand, low frequency bands (namely 183, 205 and 226 cm(-1) bands) showed small positive correlations with the stress. The piezospectroscopic (PS) coefficients of all the observed R aman bands have been determined. As an application, one of the PS coef ficients has been used to determine the stress distribution around a t riangular indentation.