Nano-scale bending test of Si beam for MEMS

We carried out a nanometer scale bending test for a single crystal silicon (Si) beam using an atomic force microscope (AFM). Nanometer scale Si beams with widths from 200 nm to 800 nm and a thickness of 255 nm were fabricated on an Si diaphragm by means of the field-enhanced anodization using AFM and the anisotropic wet etching. Bending tests for a micro- and millimeter scale beam were also carried out using an ultra-precision hardness tester and scratch tester, respectively. The mechanical property of Si beams on a nanometer scale was compared with that measured on a micro- and millimeter scale. SEM observations of the fracture surface were performed in order to reveal the size effect on the bending strength.