Transparent Conducting Films Of GaInO3 By Sputtering

Abstract

AbstractOne of the critical components used in the display device is the transparent conducting electrode. A new candidate for the transparent conductor, GaInO3 containing a tetrahedrally coordinated Ga site was identified recently, and shows good promise of improved optical transmission in the blue wavelength over ITO due to a high band gap ˜3.3 eV. Thin films of GaInO3 with cation dopants Ge for Ga, and Sn for In, respectively, have been prepared using dc reactive magnetron sputtering. Among the growth parameters, oxygen partial pressure plays the decisive role in affecting the film quality. A post-anneal in H2-rich atmosphere at 300C effectively reduced the oxygen content and lowered the resistivity to ∼3.0 mΩ-cm; however, the final resistivity appears to be insensitive to cation dopant concentrations. Concurrently, Hall measurements indicated a carrier concentration in the mid 1019 range for all films. Our structural analysis by x-ray and SEM has suggested that a limited Sn solubility in the film to less than 5 %. Doping appears to be due both to oxygen vacancies and aliovalent ion substitutions. The optical transmission of this new material is indeed superior to ITO over the entire visible spectrum, especially in the green and blue wavelengths. More work is underway to identify appropriate dopants for attaining better film conductivity.