Torsion Fatigue Testing of Polycrystalline Silicon Cross-Microbridge Structures

In the rapid advancement of micro/nano-electro-mechanical systems (MEMS/NEMS) technology, however, the reliable applications lie in the characterization of the mechanical fatigue properties of the micro/nano-structures. This paper presents the fatigue life of polycrystalline silicon (poly-Si) cross-microbridge in torsion. The torsion testing specimens are fabricated by surface and bulk micromachining. In addition, the stresses of cross-microbridge structures are investigated at various dimensions. The numerical tool ANSYS is applied to calculate the stress distribution of the testing structure. The experimental fatigue life lies between 7.78 x 10(4)-1.48 x 10(7) cycles in use of the MTS Tytron 250 microforce testing system. The collective plot of poly-Si fatigue including the results of torsion will provide the MEMS device designer and researcher a good reference in the future applications. (c) 2011 The Japan Society of Applied Physics