CHARACTERIZATION OF RF-SPUTTERED SNOX THIN-FILMS BY ELECTRON-MICROSCOPY, HALL-EFFECT MEASUREMENT, AND MOSSBAUER SPECTROMETRY

SnO(x) films, made by reactive rf magnetron sputtering onto unheated glass, were studied by electron microscopy, Hall-effect measurements, and Mossbauer spectrometry. Transmission electron microscopy showed that the films were polycrystalline with a grain size of approximately 15 nm. Hall-effect measurements gave a sharp resistivity minimum (down to 2.8 X 10(-3) OMEGA-cm) and electron concentration maximum (up to 1.2 X 10(20) cm(-3) at a specific O2/Ar gas-flow ratio during sputtering. Mossbauer spectrometry indicated that the most conducting films only consisted of the SnO2 phase, and that a SnO phase appeared at low O2/Ar ratio where it lowered the conductivity.