基于MEMS工艺的半导体电阻式气敏元件的研究

Research of Semiconductor Gas Sensor Based on MEMS Technology

介绍了半导体电阻式气敏元件工作原理,设计了一种基于MEMS工艺的薄膜气敏元件结构,此结构以Si3N4/SiO2/Si3N4复合薄膜作为支撑隔热层,蜿蜒状多晶硅作为加热层,梳状Ag电极作为气敏薄膜信号电极,SiO2作为加热层与Ag电极的绝缘层,并在SiO2绝缘层上刻蚀通孔形成加热层与金属互连。该结构具有通用性,对不同气敏特性的材料均适用,且易于改进为组合结构或阵列结构。最后,对其工艺进行了阐述。

The principle of the semiconductor gas sensor was introduced. A membrane structure for gas sensor based on MEMS technology was presented. The structure of the gas sensor mainly contains five layers. The Si3N4/SiO2/Si3N4 compound membrane was adopted as the support heat insulation layer, the zigzagged polycrystalline silicon was adopted as heater layer, the comb Ag electrode was used as the signal electrode of the gas sensor, and the SiO2 was employed as the insulated layer between heater layers. Ag electrode and the interconnect between heater layer and metal was formed by etehing hole on the SiO2 layer. The sensor structure has universal characteristic. It is applied for different materials and is easy to be improved to be the combination or array structure. Finally, the machining technology of the gas sensor based on MEMS is set forth.