Modification of mechanical properties of silicon nanocantilevers by self-ion implantation

Nanoscale silicon beams (similar to3 mum long, 250 nm wide, and 193 nm thick) were implanted with Si ions at energies of 100 and 35 keV and a dose of 1 x 10(15) ions/cm(2) and then tested using an atomic force microscope. The Young's modulus of fully amorphous silicon nanostructures (thus formed at 100 keV) was measured to be 134.5 GPa, and the modulus of bimaterial silicon nanostructures (amorphous and single crystal formed at 35 keV energy) was measured to be 150.3 GPa. Thus, the fundamental mechanical properties of 3D silicon nanostructures can be controllably modified using ion implantation at nanometer scale. This has major implications for nanoelectromechanical systems and related devices.