Effect of channel thickness on density of states in amorphous InGaZnO thin film transistor

We report on the origin of threshold voltage shift with the thickness of amorphous InGaZnO channel layer deposited by rf magnetron sputter at room temperature, using density of states extracted from multi frequency method and falling rates of activation energy, which of trends are entirely consistent each other in respect of the reduction of total traps with increasing the channel thickness. Furthermore, we shows that the behavior of Delta V-th under the positive gate bias stress and thermal stress can be explained by charge trapping mechanism based on total trap variation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3570641]