Abstract
This paper presents the design, fabrication, and characterization of CMOS (Complementary metal oxide semiconductor) micromachined grippers with on-chip photo detectors placed beneath the gripping sites. The fabrication features a combination of metal wet etch and sacrificial polysilicon etch for structural release. The fabricated microstructure contains metal and dielectric layers, plus a polysilicon heater for electrothermal actuation. For an applied power of 6 mW, one arm of the gripper produces a 3.6-□m in-plane displacement and a 1.6-□m out-of-plane displacement. The corresponding heater temperature is 220□C, and the temperature elevation at the tip is only 28□C. The measured sensitivity and dynamic range of the photo detector are 1.42 V/lux□sec and 48.5 dB, respectively. For measurements with and without grabbing a polystyrene bead, the difference of sensed voltages is 0.06 V at 100 lux. In this project, we try to introduced a novel integrated CMOS-MEMS structure which can perform thermal actuation and optical detection. We believe that it will be a great contribution to make micro gripper array with optical detection in a conventional CMOS process.