Theoretical and experimental study of heat conduction in as-prepared and oxidized meso-porous silicon

Recently measured low thermal conductivity of as-prepared and slightly oxid ized meso-porous silicon (meso-PS) offers new possibility to apply this pro mising material for thermal isolation in microsensors and microsystems. We report here a theoretical model describing specific mechanisms of heat tran sport in as-prepared and oxidized meso-PS. The model is in good agreement w ith experimental data obtained earlier. In order to compare the thermal con ductivity values of meso-PS layers oxidized at different temperatures with each other and with thermal conductivity of monocrystalline Si, a series of photoacoustic measurements was carried out. Evolution of the thermal condu ctivity along with oxidized fraction of Si in meso-PS has the same dynamics as that described by the theoretical model. (C) 1999 Elsevier Science Ltd. All rights reserved.