Influences of Sputtering Power and Substrate Temperature on the Properties of RF Magnetron Sputtered Indium Tin Oxide Thin Films

Abstract

Indium tin oxide thin films have been deposited on glass substrates using rf magnetron sputtering at different power densities (0.27–0.80 W/cm 2 ) and at different substrate temperatures (RT-250) °C. Film structure, crystallite size and orientation, optical absorption and bandgap have been studied to characterize the films. Carrier concentration and Hall mobility have been determined by Hall effect. X-ray diffraction (XRD) analysis of room temperature (RT) deposited samples reveals a structural change from amorphous to mixed amorphous/polycrystalline structure with <100> preferred orientation with increasing rf power density. The increase in substrate temperature results in a similar structural evolution from amorphous to a mixed phase followed, at temperatures higher than 200°C, by a polycrystalline phase with <111> orientation. The study clearly indicates that ITO films dominated by oxygen vacancies prefer to grow with <100> oriented crystallites whereas the <111> oriented films are characterized by a more effective doping by tin.