Development Of Silicon-based MEMS Benzene Sensor And Research Of Its Detection Technology

Benzene is not only a major pollutant in the indoor environment, but also adangerous chemical raw material, which seriously affects people’s health and lifeand property safety. And the rapid detection of benzene cannot achieve throughspectrophotometry and chromatography, and the two methods have thedisadvantage of complex operation, the test results of vary from person to person,large testing equipment and expensive. Therefore, the development of a portablefield benzene detection device is very necessary.This topic mainly aiming at the shortcomings of the traditional benzenedetection and the current domestic market demand, based on gas sensitivemechanism analysis of the polymer/inorganic hybrid gas sensitive material,combined with silicon-based MEMS process, designed a silicon-basedPANI/SnO2MEMS microstructure benzene sensor to the realize high precisionand rapid on-site detection of benzene.In this paper, the main research contents are as follows:1. Designed a new silicon-based MEMS microstructure sensor. According tothe design requirements designed micro-hotplate concrete structure and size,simulated temperature distribution of microstructure using ANSYS10.0finiteelement simulation software, verified the feasibility of the process.2. Completed the preparation of silicon-based MEMS benzene sensor. Bymeans of magnetron sputtering, photolithography and wet etching processprepared micro sensor electrode; synthesized separately PANI gas sensitivematerial through chemical oxidation synthesis and SnO2gas-sensing materialsthrough sol gel method and PANI/SnO2hybrid gas sensitive material through thehydrothermal synthesis. And manufactured sensor by laser cutting, sensitivematerials coating, sintering and welding wire encapsulation process.3. Tested the performance of silicon-based MEMS benzene sensor, including gas concentrations, sensitivity and selectivity, and analyzed the test results.4. Designed hardware detection circuit for silicon-based MEMS benzenesensor, including chip and environment temperature measuring circuits, heatingcircuit, gas concentration signal conditioning circuit; and designed thecorresponding firmware program.Silicon-based MEMS benzene sensor prepared has characteristics of smallsize, low power consumption, uniform temperature distribution, response time of33s, recovery time of33s, detection range of0.1ppm-90ppm, the optimumworking temperature of20℃-25℃, and good selectivity for benzene, ammonia.But the consistency and repeatability of sensor are poor, and need to be furtherimproved.