DIRECT OPTICAL CONTROL FOR A SILICON MICROACTUATOR

We propose a simple device, fabricated by standard Si processing, which unites for the first time direct optical signal control and micromechanisms. A Si cantilever forming the top plate of a capacitor deflects when a potential is applied. The generation of a photocurrent can control its position. A cantilever 600 × 50 × 1 μm with a gap 12 μm would use bias ∼6 V and optical power < 1 m W cm-2 to actuate 4 μm in ∼30 μs in the photoelectric scheme. Preliminary experiments with a gap ∼300 μm and d.c. biases 5-20 V demonstrate that a photocurrent flows, even in an air environment, sufficient to deflect the cantilever end some 30% of the gap under various white light illuminations of 0-1 W cm-2. © 1990.