Determination of the mechanical properties of MEMS (microelectromechanical systems) materials is necessary for accurate device deisgn and reliability prediction. This is most unambiguously performed using MEMS-fabricated test specimens and MEMS loading devices. We describe here a wafer-level technique for measuring the bend strenght, fracture toughness, and tensile strength of MEMS materials. The bend strengths of surface-micromachined polysilicon, amorphous silicon, and polycrystalline 3C SiC are 5.1+-1.0, 10.1+-2.0, and 9.0+-1.0 GPa, respectively. The fracture toughness of undoped and P-doped polysilicon is 1.2+-0.2 MPam~(1/2), and the tensile strength of polycrystalline 3C SiC is 3.2+_1.2 GPa. These results include the first report of the mechanical strength of micromachined polycrystallien 3C SiC.
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