Influence of substrate temperature on the properties of indium oxide thin films

Pure indium oxide (In2O3) and SnO2-doped In2O3 (5 and 10 wt %) films were deposited on glass at different substrate temperatures (T-s) ranging from room temperature (RT = 25 degrees C) to 350 degrees C using pulsed laser deposition. At low T-s (RT to 100 degrees C), pure In2O3 films yielded the lowest resistivity of (1.8-2.5) x 10(-4) Ohm cm and the resistivity increased sharply with an increase in T-s, and the rise in the resistivity of pure In2O3 films resulted mainly from a decrease in carrier concentration and Hall mobility. For SnO2-doped In2O3 films, the resistivity decreased from 3.5 x 10(-4) to 1.3 x 10(-4) Ohm cm with increasing T-s from RT to 350 degrees C and the reduction in the resistivity is associated with thermal activation of Sn leading to an increase in carrier concentration. Amorphous films were obtained at RT, but from T-s of 100 degrees C, the films appeared polycrystalline with orientation in the [111] plane. From atomic force microscopy, minimum surface roughness (R-a) less than or equal to 1.3 nm was obtained at RT and T-s > 200 degrees C. Between 100 and 150 degrees C. R-a was maximum (2.5-3.4 nm). The films also exhibited high optical transmittance (> 85%) to visible light. (C) 2000 American Vacuum Society . [S0734-2101(00)02203-X].