ELECTRICAL AND STRUCTURAL-PROPERTIES OF INDIUM TIN OXIDE-FILMS DEPOSITED BY REACTIVE DC SPUTTERING

High-quality indium tin oxide (ITO) films were deposited by reactive D c sputtering on glass and quartz substrates. Both pure H2O vapour and O-2 were used as reactive sputtering atmospheres. The electrical param eters, free carrier concentration and carrier mobility as well as the resistivity of the ITO films were optically and contactlessly determin ed from in reflection spectra by applying the Drude theory. Electrical properties of ITO films were examined as a function of deposition par ameters, layer thickness and annealing procedures. The DC-H2O-sputtere d ITO films show improved electrical properties because of a high free carrier concentration of N = 6.2 x 10(20) cm(-3) immediately after de position compared with a maximum of N = 4 x 10(20) cm(-3) for DC-O-2-s puttered ITO films occurring only after thermal annealing. Moreover, a nother annealing characteristic of DC-H2O-sputtered ITO films was dete cted because of their increasing resistivity during N-2 annealing in c ontrast to DC-O-2-sputtered ITO films. The low resistivity of ITO film s, deposited by application of H2O as a reactive sputtering atmosphere , is due to an improvement in crystallinity and an increase in the don or level of Sn and O vacancies.