Structure, electrical and gas sensor properties of Sn-Y-O thin films, prepared by reactive ion-beam sputtering

Experimental data on the structure, electrical and gas sensor properties of Sn-Y-O thin films with Y content from 0.4 to 4.8 at% are presented. The films have been prepared by reactive ion-beam deposition in argon atmosphere with oxygen addition. Composite target used in deposition procedure represents a tin plate with yttrium strips unevenly arranged on the plate surface. Such a target configuration allowed one to obtain 75 samples with yttrium concentration 0,4 to 4,8 at% in one deposition cycle. The structure of the Sn-Y-O films in the initial state is amorphous. The crystallization process in the system studied is observed at temperatures of 400 - 500°C, and it begins with the formation of metastable SnO precipitates. The start temperature of the crystallization process increases with increasing of the Y content. Further increase of the temperature leads to a transformation of a part of the SnO phase into SnO2 and formation of crystalline Y2O3. The studies of electrical properties of the Sn-Y-O thin films in the initial state show that electrical resistivity measured at room temperature is higher than 1010Ohm•сm and decreases with an increase of temperature. After heat treatment, leading to crystallization of Sn-Y-O thin films, electrotransport process at room temperatures is thermally activated with an activation energy about 0.23 eV. After crystallization the Sn-Y-O films show hydrogen gas-sensitivity properties. Particularly, the injection of hydrogen into argon at 350°C leads to a more than 60% decrease of electrical resistance for Sn-Y-O nanocrystalline thin film with Y concentration of 4.8 at%.

Influence of silicon impurity on the structure and physical properties of Sn-Si-O films

S.I. Rembeza, N.N. Kosheleva, E.S. Rembeza, T.V. Svistova, A.A. Vinokurov