Room temperature growth of indium-tin oxide on organic flexible polymer substrates using a new reactive-sputter deposition technology

Abstract

The ability to grow good quality transparent conductive oxides (TCOs) such as indium-tin oxide (ITO) at room temperature on flexible organic substrates is of increasing importance to industry. This is fuelled mainly by emerging technologies such as flexible flat panel displays (FFPDs) and organic light-emitting diodes (OLEDs). Standard growth techniques often require elevated substrate temperatures, rendering them unsuitable for growth on heat-sensitive polymers. In this paper, we have used a new sputtering technology to reactively sputter-deposit good quality ITO on a flexible polymer substrate that was maintained at less than 50 °C. The system is inherently stable and does not require closed-loop feedback mechanisms to control the oxygen flow, such as the ones often found in commercial magnetron systems dedicated to ITO deposition. The electrical resistivity of the ITO we obtained was 5 × 10-4 Ωcm, and the absorption coefficient was around 4000 cm-1, in the visible range. We also investigate the fundamental issues involved in the oxidation reaction process. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.