High-frequency surface acoustic wave resonator and preparation method thereof

Abstract

The invention discloses a high-frequency surface acoustic wave resonator and a preparation method thereof, relates to a microelectronic device for 5G communication, and provides the scheme for solving the problems of high bonding transfer temperature, low electromechanical coupling coefficient and the like in the prior art. A first bonding metal layer is arranged on the end face, away from the first substrate, of the high-sound-velocity substrate, a second bonding metal layer is arranged on the end face, away from the interdigital electrode, of the piezoelectric film, and bonding processing of the piezoelectric film and the high-sound-velocity substrate is completed through the first bonding metal layer and the second bonding metal layer. The method has the advantages that the method is compatible with a low-temperature metal bonding process, the working temperature of metal bonding is lower, and the thermal stress of a device can be greatly reduced. And secondly, metal bonding can enable a bonding interface to obtain higher bonding energy, and the device is more stable. Besides, the X-cut lithium niobate is used as the piezoelectric film, and the included angle of 44 degrees is formed between the vertical direction of the interdigital electrode and the Z axis of the piezoelectric film, so that a higher electromechanical coupling coefficient can be obtained, and the bandwidth of the device is improved.

Description

technical field [0001] The invention relates to a microelectronic device for 5G communication, in particular to a high-frequency surface acoustic wave resonator and a preparation method thereof. Background technique [0002] Surface acoustic wave resonators (SAW) are widely used in the field of wireless communications. However, with the development of wireless communication technologies such as social networks and the Internet of Things and the rapid growth of related business requirements, especially the arrival of 5G mobile communications, it is required that acoustic wave resonators work in Higher frequency and greater bandwidth. However, when the frequency of the surface acoustic wave resonator increases, its bandwidth decreases rapidly and the loss increases. Therefore, the operating frequency of the current surface acoustic wave resonator is generally lower than 3GHz. In order to meet the needs of 5G communication, how to improve the operating frequency and bandwidth ...

AI Technical Summary

Problems solved by technology

However, most of the piezoelectric films obtained by the deposition process are polycrystalline, and it is difficult to obtain a high preferred orientation, which leads to the generation of parasitic clutter and makes it difficult to control the frequency response of the device.

The single crystal piezoelectric thin film is generally prepared by direct bonding process, but this process generally requires annealing at a temperature greater than 400°C. Due to the different thermal expan

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