Depth profiling of strain using micro-Raman measurements

We describe a method to determine the variation of strain with depth in a s ample using Raman measurements. The method involves recording Raman spectra using incident light having different absorption coefficients. These can b e obtained using a single incident light frequency by adjustment of the poi nt of focus. The Raman spectra are then processed using a Laplace transform to obtain the characteristic elastic strain as a function of depth. The me thod is illustrated using several model strain distributions. It is applica ble to practical. cases such as graded interfaces and strained/relaxed epit axial layers.