Comparison of crystal structures among CAAC-InGaZnO, nc-InGaZnO, and solution-processed InGaZnO

In order to fabricate a highly reliable InGaZnO-TFT, it is important to form a highly crystalline InGaZnO film with few defects. Evaluation of the crystallinity of InGaZnO is necessary for improving a reliability of InGaZnO-TFT. This paper presents comparison of crystallinities among three kinds of InGaZnO films, which are a CAAC-InGaZnO film having c-axis alignment, a nano-crystalline InGaZnO (nc-InGaZnO) film including significantly nano-order crystal grains, and a solution-processed InGaZnO film having low density. As a result of the comparison, it was found out that even the least crystalline solution-processed InGaZnO film partly includes crystal regions. Further, the results also revealed that it is hard to form uniformly amorphous InGaZnO.