| 학회 | 한국재료학회 |
| 학술대회 | 2013년 가을 (11/06 ~ 11/08, 제주롯데호텔) |
| 권호 | 19권 2호 |
| 발표분야 | A. 전자/반도체 재료(Electronic and Semiconductor Materials) |
| 제목 | Highly Sensitive MOSFET Hydrogen Sensor with Thermally Isolated Structure |
| 초록 | In this study, a compensation method was developed using a reference FET with no hydrogen gas response and a sensitive FET with the same electrical performance. The FET with the same gate metal, which had an identical work function, was unaffected by hydrogen gas, and was integrated with a Pt-FET. In addition, to reduce the heat loss in the dielectric membrane, the sensor platform was thermally isolated from the substrate through two successive Si-micromachining process steps. The electrical characteristics, thermal properties and hydrogen gas sensing performance were analyzed for the fabricated sensors. The gas sensing measurements were performed in a continuous gas flow system to control the H2 gas concentration. The gas sensing signals to H2 gas were investigated by measuring the drain current change. The thermal mass and the power dissipation of the sensor can be minimized by the thermal island design. The effect of the silicon island structure was examined using a FEM simulation. Precise temperature control in the sensing element and the power consumption of the fabricated sensor device were achieved using the micro-heater operation. The fabricated sensor device showed low power consumption; 45.5 mW and 68.4 mW at 150°C and 200°C, respectively. With the gas sensing test at the H2 gas of 5,000 ppm, the changes in the drain currents of sensing FET were 0.054 mA, 0.060 mA, 0.084 mA, 0.112 mA, 0.074 mA and 0.071 mA during the micro-heater was operated at room temperature, 50°C, 100°C, 150°C, 200°C, and 250°C, respectively. From these experimental results, sensor operation at 150°C showed the best performance to hydrogen gas due to the highest sensitivity and stable response/recovery characteristics. The response and recovery times were 18 sec and 19 sec, respectively at this temperature. The developed dual-MOSFET sensor showed good performance as a hydrogen gas sensor, such as low power consumption with thermal island formation, stable gas sensing responses at various operation temperatures, and fast response/recovery times. |
| 저자 | 김범준, 김정식 |
| 소속 | 서울시립대 |
| 키워드 | Gas sensor; hydrogen; MOSFET; low power; bulk micromachining |
