Low temperature deposition of ITO on organic films by using negative ion assisted dual magnetron sputtering system

In a magnetron sputter type negative metal ion deposition, the influence of positive bias voltage (Vb) on the surface morphology, electrical resistivity, optical transmittance, and microhardness of ITO prepared on organic polycarbonate films has been investigated. In this study, the Vb increased from 0 to 250 V to attract secondary negative In and Sn metal ions, which were produced from ITO target by surface negative ionization with intense Cs ion bombardments. During deposition although reactive oxygen gas was not introduced into the chamber, by adjusting Vb at 100 V, ITO films on polycarbonate substrate with resistivity as low as 6.1×10−4 Ω cm and transmittance over 90% at 550 nm have been obtained without intentional substrate heating.AFM measurement also shows that surface roughness varied significantly with Vb. However, too intense ion bombardment originated by high Vb (>100 V) condition increased surface roughness and as a result deteriorated the electrical and optical property of ITO films.