Gas Sensing Characteristics of Undoped and Sb-doped Tin Oxide Thin Films by the Sol-gel Spin-coating Technique

Thin films of undoped SnO₂and Sb-doped SnO₂were prepared by a sol-gel spin-coating method on a silicon substrate, and the possibility of practical application in the area of the micro gas sensor fabrication was proved. The Sb-doped SnO₂film shows higher sensitivities to H₂S, H₂, C₂H_5OH and CO gases at 300℃ or 400℃ than the pure SnO₂film. It seems that the Sb doping into the film depressed the grain growth during sintering and result in increasing the sensitivities of the film to the various gases. The Sb atoms added into SnO₂film also retarded the response and recovery times of the fabricated film. The fabricated SnO₂and Sb-doped SnO₂films were well patterned with a 5㎛ resolution by aqueous solution of HI(hydroiodic acid) without lowering sensitivities to the various gases.