Research And Test On Surface Acoustic Wave Gas Sensor Performance

Surface Acoustic Wave (SAW) gas sensor has drawn great attention in academic and industrial fields because of its rapid response to time, high sensitivity, Stability, small size, low cost, etc. It has long being a hot topic in the field of sensor research. As a sensitive film SAW gas sensor testing of gas in the central part of its sensitivity, stability, selective, performance of the sensor important factors. However, due to the SAW design and production processes, their performance is not satisfactory, particularly high performance SAW Delay Line Processing difficulties, the tiny processing level is very high, it is difficult to set quantified production, the existing level of skills more restrained the components of the high frequency and the design flexibility. In this paper, a SAW sensor design choices and for its special structure and to process the request, e-beam lithography, X-ray lithography and lift-off technology combined successfully developed a frequency of 120MHz dual-channel SAW delay-line sensor devices. SAW sensor device using a NO2 gas test. Te deposition at room temperature-sensitive membrane can be detected 10ppm of NO2 gas, which is also useful for the future road of SAW sensors to do further exploration.Main research topics include:1. SAW gas sensors to developments in the overview. On the domestic and foreign SAW gas sensors development status, and discussed the sensor SAW study trends, SAW sensors to study the cushion.2. Introduced the basic theory of SAW sensors:piezoelectric Rayleigh wave and its application in the nature of the surface acoustic wave generation and reception theory, Inter-digital transducer (IDT, Inter-Digital Transducer) features and parametric analysis. To master the device characteristics and the development of preparation.3. Study of high Q value and low insertion loss SAW delay line sensor design parameters of the options, including the substrate material and electrode material selection, design of oscillator, temperature stability and other issues. Studied the SAW sensor processing technology and the sensitive membrane coating methods, formulate a reasonable and sensitive film SAW sensor selection techniques route.4. Studied the SAW sensor principles of adsorbed gases, analyzes the sensitive film and the relationship between the sensor performance, choose the Te-sensitive film NO2 gas as the test material, tested at room temperature, the sensitivity can reach 10ppm, and response time and response over time short, analysis of Te adsorbed NO2 gas sensing film theory, the use of AFM surface analysis to validate its principles.