Influence of the initial layers on the optical and electrical properties of ITO films

The influence of early stage growth structure of indium tin oxide (ITO) thi n films, deposited by reactive thermal evaporation (RTE) on optical and ele ctrical properties, was studied by atomic force microscopy (AFM) measuremen ts. ITO thin films were deposited at T-s = 440 K from an In:Sn alloy in the presence of added oxygen with (series A), and without (series B) a shutter between the substrate and the crucible. In series A, the presence of cryst allisation seeds smaller than 20 nm was observed in the initial stages of g rowth. The mean grain size value and the number of grains per aggregate inc reased with film thickness reaching, respectively, 50 nm and 8 for t = 100 nm. In series B, the initial stages show the presence of individual feature s with characteristics dimensions of up to 100 nm scattered on the surface. With increasing thickness ITO thin films of series B appear to grow simila rly to series A. In series A, both transmittance and sheet-resistance were improved. (C) 2001 Elsevier Science B.V. All rights reserved.