Out-of-plane electrothermal actuators in silicon-on-insulator technology

A novel electrothermal micro-actuator capable of actuation after being rotated 90 degrees out of plane is presented. The actuator is fabricated and characterized using the Micragem silicon-on-insulator (SOI) process developed by Micralyne Inc. The actuator is designed to be rotated out of plane by means of a serpentine spring design that provides electrical contact to the substrate while applying a downward force to hold the actuator in place. The eventual purpose of this actuator is to adjust the position of a micromirror at a 90 degrees angle to the substrate. Tbe actuator performs as expected in the horizontal position and can be assembled using standard microprobes. The actuator performance and the theory of spring operation are presented using an analytical heat transfer model, finite element modelling, and device measurements.