Effects of Nb2O5 and SiO2 buffer layers on the suppression of potassium out-diffusion into indium tin oxide electrode formed on chemically strengthened glass

Abstract

We have investigated the electrical properties of indium tin oxide (ITO) thin films deposited on chemically strengthened glass (CSG) substrate by room-temperature ionized physical vapor deposition (IPVD). The ITO thin film on the CSG substrate shows a higher sheet resistance after high-temperature anneal process (> 200 degrees C) possibly due to the out-diffusion of potassium ions (K+) from the CSG. We have improved the electrical properties of the ITO thin film by inserting Nb2O5/SiO2 buffer layers between the ITO layer and the CSG substrate. As a result, a protected and index-matched 30-nm-thick ITO thin film with sheet resistance less than 120 Omega/sq and optical transmittance higher than 90% (at 550 nm) has been achieved. (C) 2014 The Japan Society of Applied Physics