Properties of SnO2 films fabricated using a rectangular filtered vacuum arc plasma source

Transparent and conducting SnO2 films of 57-200nm thickness were deposited on microscope glass slide substrates, using a rectangular filtered vacuum arc deposition system. The 40 glass slides were equally distributed on a 400 x 420mm substrate carriage, and were exposed to a Sn plasma beam, produced by a rectangular vacuum arc plasma gun with a Sn cathode, and passed through a rectangular magnetic macroparticle filter towards the substrates. The carriage with the substrates was transported past the 94 x 494mm filter outlet. The SnO2 films were fabricated on the glass substrates at room temperature by maintaining the chamber oxygen background pressure at 0.52Pa. The film composition, and electrical and optical properties were studied as a function of the film thickness. The films were stored under ambient air conditions, and their electrical resistance was measured as a function of storage time over a period of several months. The average resistivity of films was 10-17mΩ cm for films with thickness (t) less than 100nm, but that of t > 100nm it was 5-9mΩ cm. The resistivity of the films with t > 100nm did not change significantly after 8months of storage in ambient air. The optical transmittance of the films in the visible spectrum was in the range of 75-90%. The optical constants, i.e., the refractive index and the extinction coefficient of the films at wavelength λ = 550nm were in the range of 2.02-2.09 and 0.013-0.023, respectively, and the optical band gap energy was 4.15-4.21eV. Unlike the electrical resistivity, the optical parameters weakly depended on t