Laser local oxidation of porous silicon: a FTIR spectroscopy investigation

The local oxidation of porous silicon (PS), induced by a focused laser beam, could represent an alternative method for patterning PS through direct writing. Important phase changes take place on PS when irradiated by a focused laser beam and moreover a complete confinement of the oxidized areas can be achieved due to the very low thermal conductivity of PS. We present a detailed Fourier Transform Infra-Red (FTIR) study of the irradiated areas to understand the degree of oxidation and the type of oxide obtained at different laser powers. An interpretation of the low wavenumber range, below 1300 cm(-1), in terms of Frohlich interactions will be discussed. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.