Surface acoustic wave device capable of suppressing transverse mode and manufacturing method thereof

Abstract

The invention discloses a surface acoustic wave device capable of suppressing a transverse mode. The surface acoustic wave device comprises an interdigital electrode arranged on a piezoelectric substrate, wherein an edge region of the interdigital electrode is provided with a replacement part of which material density is different from material density of a main body part of the interdigital electrode. The invention further discloses a manufacturing method of a surface acoustic wave device capable of suppressing a transverse mode. According to the invention, materials with different density are adopted to replace electrode materials in a specific region (such as an edge region) of an interdigital electrode, so that a sound velocity of the region is reduced; and a shape of a finger strip does not need to be changed, and the technical problems that in the prior art, a piston structure is relatively high in photoetching difficulty and difficult to apply under high frequency are solved.

Description

technical field [0001] The invention belongs to the technical field of surface acoustic waves, and in particular relates to a surface acoustic wave device capable of suppressing transverse modes and a manufacturing method thereof. Background technique [0002] The traditional SAWF based on LiTaO3 has a large temperature drift coefficient (about 35ppm), which leads to a large difference in the performance of the SAWF when used at different temperatures. In order to reduce the temperature drift coefficient, the method of adding SiO2 temperature compensation layer is used to reduce the temperature drift coefficient of the device (can be reduced to 0-15ppm), and the SiO2 temperature compensation layer inevitably introduces Rayleigh waves, Rayleigh waves and leakage The coupling of waves will produce strong transverse resonance (harmful clutter). In turn, spurious transverse modes are generated between the resonant frequency and the antiresonant frequency of the resonator, resul...

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Problems solved by technology

In the related art, there is a method of modifying the edge of the finger with a larger duty cycle on the edge of the finger to reduce the sound velocity in this area and suppress the transverse mode with a higher metallization ratio; A small gap increases the difficulty of lithography and is difficult to apply at high frequencies; in addition, it also destroys the continuity of the fingers in this area, and it is easy to introduce other parasitic modes

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