Study On New Resistance-Type Sensor With 3D-Sensitivity Effect

Industry and agriculture are blooming with the development of technology.However, more and more gas is generated in the process of modern industrial and agricultural production, most of them are toxic or combustible. Gas leaks, explosions and other accidents occur frequently in human life. So, in order to protect people's lives and property, we must detect theses gases quickly and alarm before the accident risk.Gas sensors plays an important role in people's lives and industrial production,As gas sensors are becoming more and more widely used, the requirement for the response speed and sensitivity of gas sensors is becoming higher and higher. To shorten the response time and improve the sensitivity of gas sensor, the optimization structure design of the traditional gas sensor is proposed.Firstly, the paper elaborates on the principle and classification of gas sensor. Based on MEMS technology, two novel gas sensor structure models are presented by citing the concept of discrete array. The sensitive part of these two types of the model is the array which is composed of many tiny half-cylinders and trapezoidals. And the discrete solid arrays made the gas sensor have the three-dimensional sensitive characteristic. The response theoretical of the sensitive arrays is analyzed, according to the response theory of diffusion model, and the response time performance of both new structure models are analyzed and compared.The analysis results show that the response time and sensitive performance of the discrete sensitive arrays device and the discrete trapezoidals array device are superior to that of the sensor with the planar sensitive structure. In the discrete half-cylinder array device structure, the response time of the sensor increases with the length of a half cylinder shortened, but the sensitivity is increased with the length of half-cylinder decreases. When the length of the half cylinder were as 2 times,3/2 times,1 times as the diffusion depth, response times of the discrete sensitive arrays device structure were reduced by 35%,28%, 19% than the planar sensitive structure,and sensitivity of the discrete sensitive arrays device structure were as 2 times,7/3times,3times as sensitivity of the planar sensitive structure. In the discrete trapezoidals array device structure, the response speed and the sensitivity are increased with the length of the upper bottom shortened; the length of upper bottom were 1 times,3/4 times,l/2 times,1/3times the diffusion depth, response times of the discrete trapezoidals array device structure discrete were reduced by 9%,12%,17%,19% than the planar sensitive structure; and the sensitivity of discrete trapezoidals array device structure were as 1.2,1.24,1.28,1.31 times as the sensitivity of the planar sensitive structure. When the length of upper bottom were 0, response times of the discrete trapezoidals array device structure discrete were reduced by 25%, and the sensitivity of discrete trapezoidals array device structure were as 1.4 times as the sensitivity of the planar sensitive structure.