A MEMS-based implant holds the promise of an artificial ear that would let the deaf hear without external electronics. The device mimics the snail-shaped structure of the inner ear, the cochlea, that makes hearing possible. The fully integrated implant-the size of a real cochlea-has been fabricated with backside through-wafer etching using an inductively coupled plasma deep-reactive ion etch. It was based on a microelectromechanical system designed by University of Michigan associate professor Karl Grosh. While other researchers have fabricated micromachined devices that mimic aspects of the cochlea, Grosh said, "our design differs from previous work by using a beam-array structure in a fully micromachined, liquid-filled two-duct structure."