抄録
Three-dimensional micro structures fabricated by focused ion beam chemical vapor deposition (FIB-CVD) are expected to be used as structural materials for MEMS/NEMS. In this research, the square micro structures were fabricated by FIB-CVD using probe currents of 48, 200, 1300 and 5200 pA, and Vickers hardness tests of the micro structures were carried out. The Vickers tests revealed that the hardness of the micro structures depends on the probe current density. The cross-sectional TEM observations indicated that the micro structure has an amorphous phase. The results show that the consistent fabrication process of the micrometer-scale beam with both ends fixed by the FIB-CVD method was established. Mechanical properties of the micro structure with beam shape were investigated by three-point bending tests. Using a nano-indentation apparatus, the bending tests showed that Young's modulus of a beam-shaped structure was 20±2 GPa and the fracture stress was 2.2±0.1 GPa. Furthermore, SEM observation of the cleavage surface on a beam-shaped structure after failure showed brittle fracture. SEM-EDS images revealed that a homogeneous composition distribution of 94 at% carbon and 6 at% gallium over the entire micro structure.
