New fatigue damage evaluation of MEMS materials under tension-compression cyclic loading

A novel full-reversed bending fatigue tester was developed for cyclic fatigue damage evaluation of MEMS materials. This paper focuses on; 1) the design of the micro fatigue tester; 2) establishment of the bending fatigue testing procedure; and 3) revealing fatigue lives of microscale single crystal silicon (SCS) specimens. In fatigue testing, an SCS specimen was reciprocated between the twin thick-cantilevers to induce tensile and compressive stresses at both fixed ends of the specimen. The twin cantilevers played two roles; one is as an indenter for bending and the other as a detector of cyclic loading applied to a specimen. The bending load was measured by the deflection of the twin cantilevers using a laser reflection system based on an AFM technique. This research succeeded in obtaining elastic hysteresis loops of microscale specimen.