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 N H4 OH as a source for reactants. Especially, the electron concentration in ZnO was lowered to below 1015 cm-3. Good device characteristics were obtained from the inverted staggered type TFTs with ZnO:N channel and ALD Al2 O3 gate insulator; μsat =6.7 cm2 V s, Ioff =2.03× 10-12 A, Ionoff =9.46× 107, and subthreshold swing=0.67 Vdecade. The entire TFT fabrication processes were carried out at below 150 °C, which is a favorable process for plastic based flexible display. © 2007 American Institute of Physics.