A facility for characterizing the dynamic mechanical behavior of thin membranes for microelectromechanical systems

Abstract

A bulge testing system capable of applying static and dynamic loads to thin film membranes is described. The bulge tester consists of a sealed cavity, filled with a fluid, bounded on the bottom by a circular stainless steel diaphragm and on the top by the thin film membrane of interest. An actuator is used to apply either a static or a periodic force to the stainless steel diaphragm. The force is transmitted through the water to the thin film membrane. This facility provides for both accelerated lifetime testing and simulated service environment testing. The thin film membranes tested are composite stacks consisting of thin films of silicon, glass, metallic electrodes, and lead-zirconate-titanate. Pressure and deflection of a membrane are acquired simultaneously during loading. An image capture system coupled with an interferometer provides the means to capture interferograms of deflected membranes during both static and dynamic testing conditions. Images are then postprocessed to construct deflection versus pressure relationships, which can be used to extract materials’ properties. Accelerated lifetime testing is performed by subjecting the thin film membranes to cyclic loading at strain levels 45%–90% of the static failure strains. In simulated service environment testing thin film membranes are subjected to cyclic loading over a range of frequencies. For a given applied force, as the resonant frequency is approached the dynamic behavior of the thin film structures vary significantly from that observed for static loading. At resonance the deflection of a thin film membrane is almost three times that of a statically deflected membrane subjected to the same applied force.

Metal Ion Implantation for the Fabrication of Stretchable Electrodes on Elastomers

“…This method has been successfully used to study the properties of silicon, [19] silicon nitride, [20] metallic [21,22] and hard polymer [23,24] thin films, as well as complex multilayer structures. [25] Unlike the hard materials normally characterized by bulge tests, soft (Y % 1 MPa) PDMS membranes exhibit large deformations when submitted to a pressure. The bulge test equations found in the literature (see, e.g., Ref.…”

Influence of structure and chemistry on piezoelectric properties of lead zirconate titanate in a microelectromechanical systems power generation application

“…36 This testing system provides cyclic pressure applied via a fluid filled chamber, and utilizes a strobed Michelson interferometer to measure the deflection of a membrane at a given phase in the pressure cycle. Sinusoidal pressure pulses were applied at frequencies that cause the membranes and test fixture to resonate, using the bottom of the pressure cycle as the zero applied pressure level.…”

Fracture in Thin Oxide Films

“…Films were testing in a static -dynamic bulge testing system described in more detail in [11]. In summary, an interferometer is used to measure the out of plane deflection of a square membrane which is pressurized with a fluid (a gas for static testing and a liquid for dynamic testing).…”