Li Xiaodong, Bhushan Bharat, Takashima Kazuki, Baek Chang-Wook, Kim Yong-Kweon
Nanotribology Laboratory for Information Storage and MEMS/NEMS, Department of Mechanical Engineering, The Ohio State University, 206 West 18th Avenue, Columbus, OH 43210-1107, USA.
Ultramicroscopy. 2003 Oct-Nov;97(1-4):481-94. doi: 10.1016/S0304-3991(03)00077-9.
Mechanical properties of micro/nanoscale structures are needed to design reliable micro/nanoelectromechanical systems (MEMS/NEMS). Micro/nanomechanical characterization of bulk materials of undoped single-crystal silicon and thin films of undoped polysilicon, SiO(2), SiC, Ni-P, and Au have been carried out. Hardness, elastic modulus and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Fracture toughness was measured by indentation using a Vickers indenter. Bending tests were performed on the nanoscale silicon beams, microscale Ni-P and Au beams using a depth-sensing nanoindenter. It is found that the SiC film exhibits higher hardness, elastic modulus and scratch resistance as compared to other materials. In the bending tests, the nanoscale Si beams failed in a brittle manner with a flat fracture surface. The notched Ni-P beam showed linear deformation behavior followed by abrupt failure. The Au beam showed elastic-plastic deformation behavior. FEM simulation can well predict the stress distribution in the beams studied. The nanoindentation, scratch and bending tests used in this study can be satisfactorily used to evaluate the mechanical properties of micro/nanoscale structures for use in MEMS/NEMS.
设计可靠的微纳机电系统（MEMS/NEMS）需要了解微纳尺度结构的力学性能。已对未掺杂单晶硅块体材料以及未掺杂多晶硅、SiO₂、SiC、Ni-P和Au薄膜进行了微纳力学表征。使用纳米压痕仪通过纳米压痕和微划痕测量了这些材料的硬度、弹性模量和抗划伤性。使用维氏压头通过压痕测量了断裂韧性。使用深度感应纳米压痕仪对纳米尺度的硅梁、微米尺度的Ni-P和Au梁进行了弯曲测试。结果发现，与其他材料相比，SiC薄膜具有更高的硬度、弹性模量和抗划伤性。在弯曲测试中，纳米尺度的硅梁以脆性方式失效，断裂表面平整。有缺口的Ni-P梁表现出线性变形行为，随后突然失效。Au梁表现出弹塑性变形行为。有限元模拟可以很好地预测所研究梁中的应力分布。本研究中使用的纳米压痕、划痕和弯曲测试可令人满意地用于评估用于MEMS/NEMS的微纳尺度结构的力学性能。
