Porous silicon as an effective material for thermal isolation on bulk crystalline silicon

Highly porous silicon has been successfully used to crate thermally isolate d local areas on bull crystalline silicon,for the fabrication of silicon in tegrated sensors. Heat distribution and heat transfer have been simulated b y using finite element analysis: with the ANSYS software. Three cases were compared: the case or bulk crystalline silicon, the case of porous silicon and that of free standing polycrystalline silicon membranes. A flow sensor of the thermal type using porous silicon isolation has been designed and fa bricated, showing high sensitivity and rapid response. Its operation princi ple and main characteristics will be presented.