Drift-Free Single Crystalline Silicon Micromirror with Floating Field Limiting Shields

This paper presents the charging mitigation method at single crystalline silicon micromirror by means of improving the geometry around electrodes. We have now determined that tilt angle drift and stiction are due to the charging effect, and that the effect can be enormously reduced by floating field limiting shields around the electrodes and dielectric geometry. While 0.5 degrees drift was measured at the 83% voltage of the pull-in voltage from the previous micromirror model, the micromirror considering drift-free design showed plusmn0.005 degrees drift at the same percentage voltage of it. At the 97.7% of the pull-in voltage, stiction occurred after about 220 seconds from the previous micromirror model. On the other hand, newly designed micromirror did not show any pull-in effect even at above percentage of it.