The present invention generally relates to a method of manufacturing a TFT. The TFT has an active channel that comprises IGZO or zinc oxide. After the source and drain electrodes are formed, but before the passivation layers or etch stop layers are deposited thereover, the active channel is exposed to an N2O or O2 plasma. The interface between the active channel and the passivation layers or etch stop layers are either altered or damaged during formation of the source and drain electrodes. The N2O or O2 plasma alters and repairs the interface between the active channel and the passivation or etch stop layers.