TY - JOUR ID - 71414 TI - Thickness Dependence of Sensitivity in Thin Film Tin Oxide Gas Sensors Deposited by Vapor Pyrolysis JO - International Journal of Engineering JA - IJE LA - en SN - 1025-2495 AU - Hossein-Babaei, Faramarz AU - Orvatinia, Mohammad AD - Electerical Engineering, K. N. Toosi University of Technology AD - Electerical Engineering, Khaje Nasir Toosi University of Technology Y1 - 2003 PY - 2003 VL - 16 IS - 1 SP - 33 EP - 40 KW - Gas Sensor KW - Resistive Gas Sensor KW - Sensitivity KW - Tin Oxide KW - LPCVD DO - N2 - Transparent SnO2 thin films were deposited on porcelain substrates using a chemical vapor deposition technique based on the hydrolysis of SnCl4 at elevated temperatures. A reduced pressure self-contained evaporation chamber was designed for the process where the pyrolysis of SnCl4 at the presence of water vapor was carried out. Resistive gas sensors were fabricated by providing ohmic contacts on the layers obtained and the installation of a custom made micro-heaterbeneath the substrate. The sensitivity (S = Ra/Rg) of the fabricated sensors to acetone vapor contamination was measured at 270ÂșC. S increased linearly with contamination level up to 8000PPM, and saturation was observed at higher concentrations. The experimental relationship between S and thickness of the sensitive film was investigated in films obtained by CVD for the first time. It was shown that S was inversely related to the film thickness, and higher S values were recorded for thinner sensors. The upper limit for S was imposed by the conduction instabilities observed in the thinnest films deposited. UR - https://www.ije.ir/article_71414.html L1 - https://www.ije.ir/article_71414_a2c7624f7d8d52f78c4720860eaed4a7.pdf ER -