微结构气体传感器的优化设计

Optimizing design of micro-structure gas sensor

利用SiO2相对于SiNx有更低的热导率,作为膜式微气体传感器的热绝缘和电绝缘层,而单晶Si适合通过各向异性腐蚀形成倒杯状结构来支撑SiO2膜。将膜式微气体传感器中的加热器和信号电极设计在一个平面上,以减小工艺复杂度,获得较高的加热效率。利用有限元分析工具ANSYS分析比较加热器和信号电极在不同宽度与间距时的温度分布。当设定加热器宽度为50μm,信号电极宽度50μm,加热器和信号电极间距为25μm,微气体传感器将获得更低的功耗和比较均匀的中心温度分布,有利于传感器整体性能的提高。

The membrane of SiO_2,which has lower thermal conductivity compared with SiN_x,is fabricated as heat and electric insulator, and single crystal Si is apt to form reverse-cup structure through anisotropy etching.The heater and signal electrodes of micro-structure gas sensor are designed on the same plane,in order to reduce the fabrication process complication and raise the heating efficiency.The temperature distribution of heater and signal electrodes are analyzed and compared at different width and distance with the finite element analysis (FEA) tool.When the width of heater,signal electrode and distance are presumed as 50,50,25μm,the simulation results show that the micro-structure gas sensor can get low power consumption and relatively even center temperature distribution.It will be good to improve the properties of sensor.