Bulk-micromachined lithium niobate sensor and actuator for harsh environments

A lithium niobate actuator has been successfully fabricated using bulk-micromachining with a metal mask. The method reported here uses a chrome/gold mask and then etching on the lithium niobate is carried out in hydrofluoric acid at 80 °C. This results in an etch rate of 50 μm/h and an undercut of the 5.5 μm/h. The fabricated actuator used the deep trenches etched into the lithium niobate, and nickel electrodes were electroplated into these trenches. The actuator was tested but the deflection was as small as 4.9 × 10^-4 μm/V. This is because lithium niobate was not properly re-poled, so that piezoelectric deformation in the lithium niobate canceled out.