Etching study of poled lithium tantalate crystal using wet etching technique with ultrasonic assistance

Utilizing the difference in etching rates of the positive and negative domains in an acid solution, domain pattern can be fabricated on the polarity surface of a congruent lithium tantalate crystal. Our results show that the ultrasonic agitation can improve the etching rate. An enhanced factor up to six was realized under a 50 W of ultrasonic power in a mixture with volumetric ratio of HF to H2SO4 at 1:2. The dependences of etching morphology on etching time and etching etchant for congruent lithium tantalate crystal were studied. The technique is applicable to fabricating three-dimensional microstructures on the surface of ferroelectric crystals.