Piezoelectric wafer for surface acoustic wave device and preparation method thereof

• Main Authors: CHEN PEIDUO, LI YONG, SHI XUXIA, WEN XUJIE, SONG SONG, CUI KUN
• Format: Patent
• Language: Chinese; English
• Published: 22.03.2019
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; ELECTRICITY; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

The invention relates to a piezoelectric wafer for a surface acoustic wave (SAW) device and a preparation method thereof. The invention provides the piezoelectric wafer. A surface layer of the piezoelectric wafer is equipped with a lithium-rich zone and a reduction zone with a near-stoichiometric ratio structure; the thickness of the surface layer is from several microns to dozens of microns; a reduction layer with weak pyroelectric effect is arranged as a second layer; a wafer base layer is arranged as a third layer. In order to realize the multilayer structure, the invention provides a method for performing lithium-enriching treatment on lithium niobate and lithium tantalate wafers (reduced wafers) subjected to reduction treatment by adopting a gaseous phase equilibrium transportation mode (VTE). In such a manner, lithium ions are filled into lithium vacancies in the wafer surface. The invention also provides a method for utilizing an optimized silk-screen printing lithium carbonatepowder technology to redu