Note: Size effects on the tensile response of top-down fabricated Si nanobeams

The tensile response of top-down fabricated sc-Si nanobeams is inferred from the fitting of stress-strain data obtained under tensile loading conditions over a large range of deformation. The testing is performed using MEMS structures consisting of two connected beams; a highly stressed silicon-nitride (SiN) beam connected to a sc-Si specimen beam. The high tensile stress component present upon the deposition of the SiN loads the sc-Si beam once the entire structure is released. The strain and stress values are extracted independently, respectively, by scanning electron microscopy inspection and vibration frequency measurement of the released tensile MEMS structures. The tensile tests are undertaken for six thicknesses to determine the dependence of the elastic response on dimensions. The Young's modulus shows a variation of 40% for thicknesses ranging from 200 to 30 nm.