Micro-structuring of lithium niobate crystal based on domain engineering

Ferroelectric domain and surface engineering of a near-stoichiometric LiNbO₃ crystal was investigated by using a scanning force microscope. The single crystal LiNbO₃ (with 1% MgO doping) was grown by the double-crucible Czochralski method. The LiNbO₃ crystals fixed on metal substrates were polished to a thickness of ∼5 μm. The domain structures were patterned in the LiNbO₃ samples, where the domains were inverted by scanning with the cantilever on the sample while applying voltages. In addition, the negatively polarized surfaces in the patterns were preferentially etched in HF solution. As a result, surface structures with arbitrary shape on the samples were fabricated.