WHISKERS IN INDIUM TIN OXIDE-FILMS OBTAINED BY ELECTRON-BEAM EVAPORATION

Indium tin oxide thin films consisting mainly of whiskers have been de posited on glass by electron beam evaporation. Low deposition rates (3 5 Angstrom/min) and substrate temperatures in the 120-400 degrees C ra nge were used. Morphology by scanning electron microscopy, crystal str ucture, energy dispersive analysis of x-rays, and x-ray photoelectron spectroscopy compositions, optical and conducting properties of films have been studied as a function of temperature of growth and further a nnealing in air. Whiskers associate and produce flatter surfaces, the grain size increases from approximate to 390 Angstrom to approximate t o 790 Angstrom, keeping however its fibrous structure after 400 degree s C-30 min annealing. In films deposited at temperatures below 200 deg rees C, next to cubic In2O3, tetragonal Sn and cubic In2Sn2O(7-x) appe ar. During growth and after air annealing Sn4+ segregates to the surfa ce, attaining Sn/In concentration ratios of 4.6. On air annealing the optical transmittance and electrical resistance increase, in some case s from 2% to 90% and by a factor of about 4, respectively. (C) 1998 Am erican Institute of Physics.