AVS 49th International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuP

Paper TF-TuP4
Effects of Deposition Parameters and Physical Properties of Thin Films on Gas Sensing Characteristics

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Poster Session
Presenter: I. Hotovy, Slovak University of Technology Bratislava, Slovakia
Authors: I. Hotovy, Slovak University of Technology Bratislava, Slovakia
J. Huran, Slovak Academy of Sciences Bratislava, Slovakia
J. Liday, Slovak University of Technology Bratislava, Slovakia
L. Spiess, Technical University of Ilmenau, Germany
P. Siciliano, IME-CNR Lecce, Italy
Correspondent: Click to Email
Our research has been focused on the preparation and characterization of NiO thin films deposited by reactive magnetron sputtering. Small gas sensors on alumina substrate with different NiO thin films were fabricated and then were investigated their physical and sensing properties for application to nitrogen oxide. In order to apply NiO thin films to the nitrogen oxide gas sensor, NiO thin films (2000 Å) were prepared by dc reactive magnetron sputtering from a nickel metal target in an Ar@+@O@sub 2@ mixed atmosphere in two sputtering modes. Details about the deposition of NiO have been reported in previous papers.@footnote 1@ The oxygen content in the gas mixture varied from 20 to 60 %. The films deposited in the metal-sputtering mode resulted in a polycrystalline (fcc) NiO phase with nearly stoichiometric composition. On the contrary, the films prepared in the oxide-sputtering mode were amorphous and oxygen rich. The post-annealing (500°C) of as-deposited NiO thin films changes amorphous to the (fcc) NiO phase for samples prepared in oxide-sputtering mode. TEM observations revealed a dense fine-grained structure with the grain size in the range 40-100 Å. AFM showed that the surface morphology NiO films could be modified by the process parameters as the oxygen content and the pumping speed. SEM observation and EDX analyses revealed uniform morphology and homogenous dispersion of NiO, Pt and Al@sub 2@O@sub 3@ phases. The depth distribution of elements (Ni and O) in the NiO thin films was measured by AES. We have investigated the sensitivity (I@sub g@/I@sub 0@) versus operating temperature of NiO films when a concentration varied from 1 to 10 ppm of NO@sub 2@. @FootnoteText@@footnote 1@ Hotovy, I., Huran, J., Spiess, L., Hascik, S.: Sensors & Actuators B 57 (1999) 147-152.