A simple route to prepare (100) preferred orientation indium tin oxide film onto polyimide substrate by direct current pulsed magnetron sputtering

The indium tin oxide (ITO) film was deposited onto the polyimide (PI) quartz, and Si (100) substrates by the traditional direct current (DC) pulsed magnetron sputtering technology, which no any heating treatment was carried out onto the substrates. With the increase of sputtering power density from 0.83 to 8.33 W/cm2, ITO films with different crystal structure, optical, and electrical properties were obtained. X-ray diffraction results showed that with the increase of sputtering power density, the crystal structure of ITO film changed from the polycrystal without preferred orientation to (100) preferred orientation. ITO film with (100) preferred orientation showed a satisfactory optical and electrical properties, which the band gap, resistivity, and carrier concentration was about 4.05 eV, 4.91 × 10−4 Ω cm, and 5.10 × 1020 cm−3, respectively. Combining the increase rate of ITO film growth rate, sputtering voltage, and sputtering current density, as well as DC pulsed voltage waveform, the formation of ITO film with (100) preferred orientation was analyzed logically. Finally, the relationship between sputtering power density and preferred orientation, as well as optical and electrical properties of ITO film, was investigated systematically. With above results, the short time overload sputtering voltage of DC pulsed sputtering process could be an ideal choice to prepare ITO film with (100) preferred orientation, especially for substrate without high temperature resistance.