Mechanical stress relief in porous silicon free standing membranes

Abstract

In this work, we report on the difference of mechanical stress in free standing and attached Porous silicon membranes. By performing Raman analysis, we demonstrate that the tensile stress accumulated during the etching process by the porous silicon layer is partially compensated by the presence of the substrate. We highlight this complex effect by experimentally showing the balancing effect of the substrate and the change in mechanical stress between top and bottom surfaces in free standing membranes. In addition, this Raman investigation allows us to separate the effects on the Raman lineshape due to the nanostructures from those related with the mechanical stress of macroscopic structures.