Cluster Size Control toward High Performance Solution Processed InGaZnO Thin Film Transistors

Clusters in a precursor solution play an important role in metal oxide semiconductor films. Additives including acetic acid (AcOH) and acetylacetone (acac) were applied in a precursor solution to adjust the morphology and electronic performance of solution processed amorphous InGaZnO (IGZO). The average size of clusters was brought down, and size distribution was narrowed. Consequently, a film with smaller roughness was obtained. A thin film transistor (TFT) was fabricated using the IGZO film. Interface trap density was reduced by 18%. Saturated mobility increased from 4.0 to 5.5 cm2/(V s), and turn on voltage shift under positive bias stress decreased from 1.6 to 0.3 V/10000 s.