Patent attributes
A method for forming uniform, sharply defined periodic regions of reversed polarization within a unidirectionally polarized ferroelectric material proceeds as a two-step process. First, alignment keys are formed on upper and lower planar surfaces of a unidirectionally polarized ferroelectric material by producing a spaced pair of alignment key shaped domain reversed regions and etching alignment key shaped notches in the upper and lower surfaces where the domain reversed regions intersect the surface planes. These notches, being vertically aligned between the upper and lower surfaces, are then used to align photomasks over a surface coating of photoresist formed directly on the material surface or on SiO2 layers coating the material surface. The photoresist is then patterned and may also be thermally hardened to form a plurality of regularly spaced open strips, through which conducting metal contacts or ion-exchanged regions may be formed or contacts to the ferroelectric surface can be directly made by liquid conductors to produce the desired polarization reversals by application of an electric field at different temperatures of the material.
