| Summary: | 碩士 === 中國文化大學 === 材料科學與製造研究所 === 88 === The purpose of this research is to develop a semiconductor type H2S sensor with silicon-based microfabrication and micromaching technology. By using MEMS (Microelectro Mechanical System) related techniques, the sensing area of the device can be made as small as 0.3×0.3 mm2. Silicon wafer will be utilized as substrate; this allows the processes to be compatible with IC manufacturing. Therefore, sensing element and the corresponding measuring circuit are possible to be made on the same chip. Several sensing elements were contained in a 3mm×3.4mm chip. Take the advantages of IC manufacturing processes, especially the packaging method, the cost for this type of sensor can be tremendously reduced.
The WO3-based H2S gas sensor devices have been fabricated by reactive RF plasma sputtering the Platinum (Pt), gold (Au) and Au-Pt metals onto WO3 thin film. The best performance between sensitivity and response and recovery times have been obtained for Pt-doped WO3 sensor at 2200C to detect H2S gas and the sensitivity of 23 toward a level of 1ppm H2S under above working condition.
Now the we also accomplish test for temperature detector. The temperature detector has nice performance. The result of this research, the relationship of resistance and temperature are linear, and his resistance is stable in variant temperature. The temperature coefficient of resistance is 2400ppm/℃.The micro heater can be heated up to 500℃, and pass the continuous 1000 cycles test from room temperature to 500℃. It was can controlled the temperature of operation in this device. Besides, the micro heater hasn’t proceed to back etching, so it must be support large current to reach working temperature, due to waste electricity and short life.
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