Three‐dimensional spectral and spatial resolution of raman measurements in sapphire

Raman spectroscopy affords a simple and practical tool to determine subsurface stresses in oxides via the identification of spectral peak locations. To access the full utility of the technique, it is necessary to understand and quantify the role of material‐specific measurement parameters on the peak shapes and locations. This work employs systematic experiments on sapphire to examine how peak height and width influence peak identification for five different peaks: 378, 417, 576, 644, and 751 , with 417 examined in both the R‐ and C‐plane. Experiments are performed on the basal (0001) and rhombohedral (1102) planes of sapphire using different experimental magnifications. It is revealed that the accuracy of peak identification depends strongly on the wavenumber, due to peak‐specific width and decreases with lower signal intensity. Basal plane sapphire leads to lower intensity and subsequently lower accuracy. The results are presented in a way that can be used to determine the statistical accuracy of stress measurements in sapphire by Raman spectroscopy.