High performance thin film transistor with low temperature atomic layer deposition nitrogen-doped ZnO

High performance thin film transistor (TFT) with atomic layer deposition (ALD) nitrogen doped ZnO (ZnO:N) as an active layer is demonstrated. The electrical properties of ZnO thin films were effectively controlled by in situ nitrogen doping using NH4OH as a source for reactants. Especially, the electron concentration in ZnO was lowered to below 10(15) cm(-3). Good device characteristics were obtained from the inverted staggered type TFTs with ZnO:N channel and ALD Al2O3 gate insulator; mu(sat)=6.7 cm(2)/V s, I-off=2.03x10(-12) A, I-on/off=9.46x10(7), and subthreshold swing=0.67 V/decade. The entire TFT fabrication processes were carried out at below 150 degrees C, which is a favorable process for plastic based flexible display. (C) 2007 American Institute of Physics.