Characteristics of sputtered zinc-oxide films prepared by UBM sputtering for thin film transistors

In this work, we describe the characteristics of zinc-oxide (ZnO) thin films synthesized on Si (001) and Corning (7059) glass substrates by unbalanced magnetron (UBM) sputtering under various ZnO film thicknesses and RF powers. We investigated the characteristics of ZnO filmsʹ structural, optical, and electrical properties with various film thicknesses and RF powers for the active channel in a thin film transistor (TFT). We used the UBM sputtering system for high rate deposition of ZnO films. The ZnO film surface was rough and the grain size of the film increased with increasing RF power and film thickness. The electrical properties improved with the increase of RF power and film thickness. These results can be explained by the improvement of the crystallinity in the ZnO film related to the grain size increase with increasing RF power and ZnO film thickness.