The aim of this project is the development of Bulk Acoustic Wave (BAW) Solidly Mounted Resonators (SMR) using aluminum nitride (AlN) as piezoelectric, for use as high performance gravimetric sensors for the analysis of gases. The fields of application of this type of sensors are very numerous: air quality monitoring, disease diagnosis through the analysis of the exhaled air, gas analysis in vehicles, analysis of waste gases in industrial processes such as in the petrochemical industry, analysis of gases in the thermal processes of energy generation, analysis of the state of the foods (decomposition, quality of food), etc. More specifically, in this project we will focus on developing sensors and interrogation techniques when they operate at temperatures between -50ºC and 500ºC. The gravimetric sensor will consist of a SMR-BAW resonator, acting as a transducer, on whose surface (or top-electrode) a material (receiver) is deposited. The receiver selectively traps the molecules of a targeted gas, and depending on its concentration, the mass loading effect on the top electrode causes a change in its resonance frequency that can be detected by interrogating the sensor electrically, either by cable, or wirelessly. Crystal quartz transducers and Surface Acoustic Wave (SAW) resonators have been used for sensing. Compared to them, the BAW SMRs generally operate at a higher frequency, have a higher quality factor and have better temperature stability if properly designed. The higher quality factor and operation frequency, the better the resolution achieved and the temperature stability is, of course, critical for developing sensors that work in harsh environments. The project will be undertaken by a consortium of two research groups with extensive experience. In general terms, the fabrication of the transducers and the functionalization of the transducers, as well as the measurements of the final prototype will be carried out by the coordinating group of the UPM. The tasks of the UPC subproject will be: -Developing the temperature-dependent models required to design the transducers and their design to obtain maximum sensitivity to variations in mass and minimum sensitivity to changes in temperature, or alternatively, transducers with good performances even operating at high temperatures. -Evaluation of the properties of the materials and devices from -50 ° C up to 500 ° C. Complex measurement systems will be used to obtain, not only the electro-acoustic parameters of the materials involved in the design, but also their thermal parameters. -Development of remote interrogation systems for sensors working in harsh environments. The design of efficient antennas in a very broad temperature range and the circuitry and connections with the sensor will be addressed.
Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad