Properties optimization with high nitrogen content doping for InGaZnO films deposited by reactive sputtering with a GaN-embedded cermet target

GaN-embedded cermet target is used in this work for reactive sputtering to deposit the nitrogen-doped indium gallium zinc oxide (N-IGZO) films at different plasma atmospheres and to understand the heavily nitrogen doping in IGZO films for the possible application of IGZO thin film transistor (TFT) in the near future. Materials properties of N-IGZO films in crystallinity, microstructure, and electrical and optical properties were systematically investigated. The experiment showed that IGZO films with the high [N]/([O]+[N]) ratios of 0.11-0.14 showed low surface roughness of 0.26-0.43 nm, low carrier concentration of 2.36 × 1015-2.16 × 1016 cm−3, high mobility of 23-46 cm2/V s, suitable electrical conductivity of 0.0143-0.157 S cm−1, wide band gap of 3.32-3.47 eV, and high transparency of 85-89%. This is a pioneer work in IGZO film with a high nitrogen content above 10% at the anion site.