Low-power-Consumption metal oxide NO2 gas sensor based on micro-heater and screen printing technology

• Published in: Journal of nanoscience and nanotechnology Vol. 12; no. 7; p. 5543
• Main Authors: Moon, S E, Lee, H K, Choi, N J, Lee, J, Yang, W S, Kim, J, Jong, J J, Yoo, D J
• Format: Journal Article
• Language: English
• Published: United States 01.07.2012
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2012.6364

An NO2 micro gas sensor was fabricated based on a micro-heater using tin oxide nano-powders for effective gas detection and monitoring system with low power consumption and high sensitivity. The processes of the fabrication were acceptable to the conventional CMOS processes for mass-production. Semiconducting SnO2 nano-powders were synthesized via the co-precipitation method; and to increase the sensitivity of the NO2 gas rare metal dopants were added. In the structure of the micro-heater, the resistances of two semi-circular Pt heaters were connected to the spreader for thermal uniformity. The resistance of each heater becomes an electrically equal Wheatstone-bridge, which was divided in half by the heat spreading structure. Based on the aforementioned design, a low-power-consumption micro-heater was fabricated using the CMOS-compatible MEMS processes. A bridge-type micro-heater based on the Si substrate was fabricated via surface micro-machining. The NO2 sensing properties of a screen-printed tin oxide thick film device were measured The micro gas sensors showed substantial sensitivity down to 0.5 ppm NO2 at a low power consumption (34.2 mW).