Optimization of RF-Sputtered ITO Films for High NIR Transparency at Low Deposition Temperature

• DOI: 10.1557/proc-865-f14.4
• Publication Date: 2011-11-21T10:02:26Z
• Authors: J. Zhou; X. Wu; T.A. Gessert; Y. Yan; G. Teeter; H.R. Moutinho
• Keywords: 0103 physical sciences; 01 natural sciences

AbstractSn-doped indium oxide (ITO) films deposited at temperatures <250°C by r.f. magnetron sputtering are investigated for use as transparent back-contact electrodes to CdS/CdTe top cells in two-junction, mechanically stacked tandem-cell designs. Results show that carrier mobility increases with substrate temperature while beneficial changes in carrier activation occurs at a substrate temperature ~230°C. Small additions of oxygen to the sputtering environment are effective at reducing near infrared (NIR) absorption. Control of these deposition parameters has produced ITO films with NIR absorption (860–1300 nm) < 10%, and electrical resistivity of <1x10-3 ohm-cm.