Deep-ultraviolet Raman investigation of silicon oxide: thin film on silicon substrate versus bulk material

Abstract

Raman spectroscopy is a powerful experimental technique for structural investigation of silicon based electronic devices such as metal–oxide–semiconductor-type structures. It is widely used for characterization of mechanical stress distribution in silicon substrate. However, in the case of Raman measurements of oxide layer on silicon substrate visible excitation makes this technique almost useless. The reason for this difficulty is two-phonon scattering from silicon substrate which masks the signal from oxide layer. Application of deep-ultraviolet (deep-UV) excitation reduces the penetration depth of the radiation into silicon substrate about 30 times. As a result, the simultaneous measurement of one-phonon scattering from silicon substrate and the Raman spectrum of the oxide layer become possible. This work presents the study of thin silicon oxide film on silicon substrate with application of deep-UV Raman scattering. The spectra measured for thin film are compared with reference spectra obtained for bulk material.