Novel transparent conductive indium zinc oxide thin films with unique properties

Indium zinc oxide (IZO) thin films sputter-deposited on glass substrate were investigated for use as pixel electrodes of thin-him-transistor liquid-crystal display (TFT-LCD) applications. The experiments revealed that IZO thin film is suitable for use in high-performance TFT-LCDs with respect to its electrical and optical properties, and its etching performance. Cross-sectional transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses indicated hat the IZO film remains in an amorphous state after annealing in vacuum or in an N-2-added atmosphere, but that its electrical and optical properties are changed by annealing in an Nz-added atmosphere. After the latter treatment, the film's resistivity increased to about 3 times that of an IZO film annealed in vacuum; however, we found a novel transparent conductive thin film, which has over 90% transparency within the infrared range (800-3200 nm) and a resistivity of about 1.2 m Omega cm. Depth profile analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS) revealed a difference of chemical structure in the two films after annealing under different conditions.