Microscale mechanics for sensors and actuators

Microscale mechanical structures have been conceived and fabricated that make possible a wide variety of microsensors and microdynamical moving elements. Miniature sensors and microscopic moving elements on a chip are made by standard integrated-circuit fabrication techniques, augmented with special etches and deposited films. An integrated audio microphone, a miniaturized hot-wire anemometer for sensing gas flow, and an ultrasonic oscillator multisensor are some realized possibilities. Photolithographically shaped polysilicon layers, grown on an easily-etched sacrificial phosphosilicate glass layer, form tiny movable gears, sliders, springs, and cranks. Electrostatically driven micromotors less than 100 μm across have been operated successfully. Device opportunities and fundamental properties requiring investigation are described