Porous silicon membranes for gas-sensor applications

Abstract A porous silicon membrane (PSM) for an electrochemical oxygen microsensor has been achieved. Both p + - and n + -type materials have been studied. On the p + -type silicon, the porosity is found to be homogeneous through the complete thickness of the membrane, while n + -type membranes appear less homogeneous. The permeability of the PSM to oxygen has been tested with the help of a classical sensor. The diffusion process is found to be much more efficient for n + -type than for p + -type membranes. For PSM thicknesses ranging from 150 to 270 μm, the diffusion time varies from 7 to 10 min.