Walking patterns generated by coupled ZnO-on-Si3N4 bimorphs

Two parallel ZnO-on-Si₃N₄ bimorphs coupled at their free ends by a silicon nitride bridge have been fabricated on silicon wafers using sacrificial surface etching methods. The structure is to be employed in the future as legs of silicon microrobots. The bimorphs are 200 microns wide, 3 microns thick and 2066 microns long. Voltages are applied independently to the two bimorphs. Deflection of the ZnO-on-Si₃N₄ bimorphs showed a quadratic dependence on the magnitude of the applied voltage due to a combination of piezoelectric and thermoelastic effects. By controlling the applied voltages on the bimorphs, flexural bending and twisting of the coupled structure are obtained