Characterization of phosphosilicate thin films using confocal Raman microscopy

We have demonstrated a characterization tool based on confocal Raman micros copy capable of studying the vibrational spectrum of silica-on-silicon-base d thin films within a confined, similar to 1 mu m(3)-size volume beneath th e sample surface. The Raman spectra of a set of phosphosilicate thin film s amples have been quantitatively analyzed and correlated with both phosphoru s concentration C-P and refractive index n, as determined by conventional m ethods. The normalized intensity of the P=O vibration scaled linearly with C-P and n, and allowed for the calibration of the Raman measurements to a p recision of similar to 0.2 wt. %P and similar to 10(-4) in index. The capab ility of this technique for studying index and dopant profiles in arbitrary systems is also discussed. (C) 2000 American Institute of Physics. [S0034- 6748(00)01905-5].