Nondestructive measurement of machining-induced amorphous layers in single-crystal silicon by laser micro-Raman spectroscopy

Laser micro-Raman spectroscopy was used to examine silicon wafers precision machined by diamond tools, and the results were compared with transmission electronic microscopic results. It was found that near-surface amorphous layers were generated by machining and there was a strong correlation between the thickness of the amorphous layer and the Raman intensity ratio of the amorphous phase to the crystalline phase. This finding provides the feasibility of a fast, inexpensive, nondestructive and quantitative measurement approach for subsurface damages of semiconductor materials by using laser micro-Raman spectroscopy. The effective measurement range was experimentally investigated and the sensing limits were theoretically discussed from the aspect of light scattering and light absorption with a double-layer material model.