Two-axis single-crystal silicon micromirror arrays

This work presents the design, fabrication, and testing of a two-axis 320 pixel micromirror array. The mirror platform is constructed entirely of single-crystal silicon (SCS) minimizing residual and thermal stresses. The 14-μm-thick rectangular (750×800 μm²) silicon platform is coated with a 0.1-μm-thick metallic (Au) reflector. The mirrors are actuated electrostatically with shaped parallel plate electrodes with 86 μm gaps. Large area 320-mirror arrays with fabrication yields of 90% per array have been fabricated using a combination of bulk micromachining of SOI wafers, anodic bonding, deep reactive ion etching, and surface micromachining. Several type of micromirror devices have been fabricated with rectangular and triangular electrodes. Triangular electrode devices displayed stable operation within a (±5°, ±5°) (mechanical) angular range with voltage drives as low as 60 V.