Mechanical investigation of perforated and porous membranes for micro- and nanofilter applications

Perforated silicon nitride and porous silicon membranes have been fabricated using micromachining technology. The investigation of the mechanical stability of such membranes is a key issue for the proper use of such components in filtration applications. The tensile strength of the membranes under pressure has been investigated to determine the bursting pressure of perforated and porous membranes. From membrane deflection measurements an effective Young's modulus as function of the material and the geometrical properties, such as membrane size, thickness and size of the non-perforated frame width have been calculated. Perforated and porous membranes can be modeled as a non-perforated membrane with adjusted Young's modulus. Finite element simulation has been used to estimate the deflection, stress distribution and breaking properties. The measured values are compared to values derived from analytical approximation as well as from simulations.