Preparation method of surface acoustic wave sensor, and prepared sensor and application thereof

Abstract

The invention discloses a preparation method of a surface acoustic wave sensor, and a prepared sensor and application thereof. The preparation method comprises the following steps: S1, preparing an SAW chip; S2, preparing a magnetron sputtering mold; to be specific, connecting an upper mold and a lower mold by a bolt or magnetically to form the magnetron sputtering mold, arranging an SAW chip clamp slot array for placing the SAW chip in the lower mold, and opening a plurality of rectangular through holes corresponding to an SAW chip delay line region in the upper mold; S3, depositing a ZnO thin film; to be specific, depositing a nano-participle-shaped ZnO thin film having the size of 25 to 45 nm on the surface of the SAW chip by means of magnetron sputtering; to be specific, depositing theZnO thin film by means of magnetron sputtering in a multi-layer manner and adjusting magnetron sputtering parameter differences of different deposition layers to control the shape of the ZnO thin film deposited on the surface of the SAW chip. According to the invention, the surface acoustic wave prepared by the above preparation method is used for detecting the humidity in air; and the average linear sensitivity in the humidity detection reaches up to 573.4 Hz / % RH.

Description

Technical field [0001] The invention relates to a preparation method of a surface acoustic wave sensor, the prepared sensor and its application, and belongs to the field of surface acoustic wave sensors. Background technique [0002] Surface Acoustic Wave (SAW) sensor, as a new detection technology, has the advantages of miniaturization, high sensitivity, fast response speed, and low detection limit. It has become a research hotspot in related fields in the academic community. Its application fields Covers environmental monitoring, food safety, medical diagnosis, etc. [0003] SAW sensors are mainly divided into four categories, active delay line type, active resonator type, passive delay line type and passive resonator type. Among them, the SAW sensor structure of the active delay line type is mainly composed of input and output fingers. The transducer is deposited on the surface of the piezoelectric substrate. The input interdigital transducer is used to generate excitation sign...

AI Technical Summary

Problems solved by technology

In the prior art, nanostructured ZnO is mainly prepared on the surface of the SAW chip as a waveguide layer by chemical synthesis, hydrothermal method, and sol-gel method. However, these methods cannot accurately control the film thickness, and it is difficult to achieve repeatable and large-scale mass production

In order to achieve repeatable and large-scale production, there are also studies on the preparation of ZnO thin films by magnetron sputtering, but the existing technology cannot form nano-particle ZnO thin films by magnetron sputtering, and there are a large number of defects or flaws inside the thin films, while the microscopic properties of ZnO The shape and scale directly affect the performance of the final SAW sensor. Therefore, in order to obtain a relatively excellent ZnO film as a waveguide layer, it is necessary to transfer the SAW sensor after the magnetron sputtering ZnO waveguide layer to the annealing equipment, which is difficult to avoid. It will cause secondary pollution to the prepared SAW sensor

[0004] Secondly, the preparation of waveguide layers based on SAW sensors mainly relies on traditional photolithography technology. The SAW sensor substrate and electrodes cause contamination or damage, reducing its success rate

In addition, the traditional micromachining lithography process can only batch process the SAW chip array on a whole piece of ST-cut quartz wafer at a time, and cannot realize the micromachining of the surface of a single SAW device after cutting

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