Optimization of a SAW metal oxide semiconductor gas sensor
- 13 January 2003
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
Abstract
A simple theoretical model is applied to the problem of a SAW (surface acoustic wave) gas sensor which operates on the principle of conductivity changes within the sensing film. The model allows the prediction of SAW sensor response for a film of known conductivity variations, and the theoretical value of SAW velocity change agrees very well with that determined by experiment. The electroacoustic attenuation was also determined to be a significant factor in designing a SAW sensor. SAW sensor response can be optimized by designing the device such that the sheet conductivity of the film is within some region dependent upon the substrate material. A WO/sub 3/ film could be designed to have a sheet conductivity within a specific range by tailoring parameters such as film thickness, doping, and heat treatment. A sensor consisting of an ST-cut SiO/sub 2/ substrate and a WO/sub 3/ film selectively sorbent to H/sub 2/S was investigated. The SAW gas sensor is configured so that the film sheet conductivity and sensor response are measured simultaneously upon exposure to H/sub 2/S. Specific operating conditions are obtained that optimized the SAW gas sensor response.Keywords
This publication has 4 references indexed in Scilit:
- Macroscopic theory of surface acoustic wave gas microsensorsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2003
- Processes involved at the chemical interface of a saw chemosensorSensors and Actuators, 1987
- Surface acoustic wave gas sensor based on film conductivity changesSensors and Actuators, 1985
- Simple theory of acoustic amplificationIEEE Transactions on Sonics and Ultrasonics, 1971