Study of The SnO2:Ni MEMS gas sensor

• Main Authors: Zheng, Yu-Zhan, 鄭宇展
• Other Authors: Chen, Shih-Chih
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/t8q6ay

碩士 === 國立雲林科技大學 === 電子工程系 === 106 === SnO2 material has many excellent characteristics and can detect most gases, but the disadvantage is that it cannot distinguish the type of gas. In this study, SnO2 is used as a sensing material and surface-doped Ni-resistive resistive gas sensor. First, the indoor gases of volatile organic compounds (VOC) and formaldehyde (HCHO) are distinguished and the best parameters are found, and finally compared with other gases. In this research process, Si3N4/ SiO2 is first deposited by LPCVD as an insulating layer on six inch wafer P-type (100). The use of E-Gun Pt / Ti deposited it up and define the patterned as electrode, micro heater and electric film group, then use RF SnO2 as the sensing layer deposited on the electrode, then the use of E-Gun, the nickel metal respectively by 3nm, 5nm, 10nm and 20nm of different thickness deposited on the sensing layer as the catalyst layer. Then ICP-DRIE is used to etch a thermal insulation slot at the bottom of the micro heater to form a suspension structure to complete the sensor element. Finally, the best result of this experiment is Ni (3nm) /SnO2, which is annealed for 10 minutes at atmospheric temperature for 400℃, and at a certain power 136.9mW, at the operating temperature of 250℃, the concentration of VOC and HCHO is 80ppb. HCHO has super high response rate of 74% and has good selectivity. More detailed information on the research will be discussed in this paper. Keyword：Indoor air quality、SnO2、Transition metal、formaldehyde、VOC、gas sensor