ORIENTED PEROVSKITE TYPE POTASSIUM NIOBATE THIN MEMBRANE, AND SURFACE ACOUSTIC WAVE ELEMENT HAVING THE THIN MEMBRANE

摘要

PROBLEM TO BE SOLVED: To obtain an oriented perovskite type potassium niobate thin membrane having good electromechanical coupling properties by forming the (020) oriented perovskite type potassium niobate thin membrane on a crystalline substrate by a physical evaporation method. ;SOLUTION: This oriented perovskite type potassium niobate thin membrane is the thin membrane of (020) oriented perovskite type potassium niobate formed on a substrate obtained by cutting a single crystal of strontium titanate, etc., so that the (110) face may be the surface by carrying out a high frequency magnetron spattering to a target obtained by mixing a powder of potassium niobate and potassium carbonate and attaching the mixture to a quartz glass or the like, in an atmosphere of the mixed Ar gas and O₂ gas. A piezoelectricity can be improved by dipping the thin membrane in a nonconductive solution, heating the dipped thin membrane to 150-220°C, and applying a direct electric field to the heated thin membrane to carry out a polarizing treatment. The surface acoustic wave element is obtained by forming a metal layer such as Al on the thin membrane, coating a photoresist on the metal layer, drying the photoresist, placing a negative mask on the dried photoresist, irradiating ultraviolet rays thereto, dipping the irradiated product in a developing solution to remove the unpolymerized part, and heating and hardening the unremoved photoresist to provide a comb electrode.;COPYRIGHT: (C)1999,JPO