Surface acoustic wave resonator based on relaxor ferroelectric single crystal and preparation method

Abstract

The invention discloses a surface acoustic wave resonator based on a relaxor ferroelectric single crystal and a preparation method, and belongs to the technical field of surface acoustic waves. According to the technical scheme, the surface acoustic wave resonator is formed by sequentially stacking an interdigital electrode layer and a piezoelectric substrate layer. The piezoelectric substrate layer is made of a relaxor ferroelectric single crystal doped with lead indium niobate-lead magnesium niobate-lead titanate, called Mn-PIMNT for short, and 0.5 mol% of Mn-xPb (In1 / 2Nb1 / 2) O3-(1-x-y) Pb (Mg1 / 3Nb2 / 3) O3-yPbTiO3. The Rayleigh wave obtained by the surface acoustic wave resonator structure of the relaxor ferroelectric single crystal provided by the invention has a high electromechanical coupling coefficient which is up to 24%. And the orientation of the Mn-PIMNT relaxor ferroelectric single crystal in different polarization directions is optimized by rotating an Euler angle, and the surface acoustic wave with high performance is preferably selected, so that the method is very suitable for a large-broadband surface acoustic wave device.

Description

technical field [0001] The invention relates to the technical field of surface acoustic waves, in particular to a surface acoustic wave resonator based on a relaxation ferroelectric single crystal and a preparation method. Background technique [0002] Surface Acoustic Wave (SAW) devices are widely used in filters of radio frequency front-ends of communication equipment due to their high performance, low loss, miniaturization, and low cost. In the field of smartphone RF front-ends, acoustic filters are mainly used, including SAW (surface acoustic wave) filters and BAW (bulk acoustic wave) filters. Huge application requirements will also put forward higher requirements for SAW devices, with a larger electromechanical coupling coefficient (K 2 ) piezoelectric substrate material is the key to device design. Therefore, in order to develop SAW devices that can meet the development trend and application requirements, domestic and foreign experts have been constantly searching fo...

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Problems solved by technology

At present, traditional piezoelectric single crystal materials (such as lithium niobate (LiNbO 3 , LN) and lithium tantalate (LiTaO 3 , LT) are the most commonly used piezoelectric substrate materials for commercial SAW devices. They have certain limitations. The typical cut-type electromechanical coupling coefficients used are not high. For example, the electromechanical coupling coefficient of 42°Y-X lithium tantalate is 7.2 %, the electromechanical coupling coefficient of Y-Z cut type is only 0.6%

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