Tin oxide nanowire sensors: fabrication process simulation and electrical modeling

During the last decades, many fields (e.g., from disease diagnostics to environmental monitoring and from industrial process control to safety systems) have had increased demand for highly sensitive, small size and portable gas-sensing devices. In this scenario, metal-oxide based chemiresistive gas sensors, which responses depend on the change in their electrical conductance upon interaction with the target gas, have been widely studied and commercialized. Tin oxide (SnO2) is one of the widely used and most important metal-oxide semiconductor used in gas sensors mainly due to its sensitivity to different gaseous species. Metal oxide nanowires have demonstrated improved properties compared to the conventional thick film gas sensors mainly due to their huge surface-to-volume ratio, which leads to improved gas response. The first part of this work is a literature review of the metal oxide gas sensors. Metal oxide semiconductors, general gas-sensing mechanisms and fabrication processes of metal oxides nanowires gas sensors are introduced as well as the vapor – liquid – solid growth method and RF magnetron sputtering and lift-off for the bottom-up and top-down fabrication process approaches, respectively. The second part is instead focused on the simulation of the fabrication process of a tin oxide nanowire gas sensor based on the top-down approach. Sentaurus Process and Sentaurus Topography 3D were used for the process simulation while Sentaurus Device was used for the electrical simulation.