Journal of Microelectromechanical Systems vol:19 issue:4 pages:982 -991
Abstract--- This paper reports on the fabrication of micro actuators through wafer-level integration of pre-strained SMA wires to silicon structures. In contrast to previous work, the wires are strained under pure tension, and the cold state reset is provided by single crystalline silicon cantilevers. The fabrication is based on standard MEMS manufacturing technologies and enables an actuation scheme featuring high work densities. A mathematical model is discussed, which provides a useful approximation for practical designs and allows analyzing the actuators performance. Prototypes have been tested and the influence of constructive variations on the actuator behavior is theoretically and experimentally evaluated. The test results are in close agreement with the calculated values, and show that the actuators feature displacements among the highest reported.