Raman microscopy using a scanning near-field optical probe

A scanning near-field optical microscope (SNOM) has been coupled to a comme rcial Raman spectrometer to produce an instrument capable of obtaining Rama n spectra with a spatial resolution of 100-200 nm. This resolution is three to ten times greater than is typically possible using a conventional diffr action limited system. Sub-micron resolution Raman images of a damaged sili con wafer have been obtained and the position of the peak analysed to produ ce a high resolution map of stress around a micron sized scratch. The resul ts are compared with data obtained with a conventional Raman microscope. Th e current performance limits of the Raman SNOM instrument are discussed and possible technical improvements suggested; the latter indicate that near-f ield Raman spectroscopy will be a feasible technique for high spatial resol ution characterisation of semiconductor surfaces. (C) 1998 Elsevier Science B.V. All rights reserved.