Vertically integrated submicron amorphous-In2Ga2ZnO7 thin film transistor using a low temperature process

In this work, vertically integrated amorphous-In2Ga2ZnO7 (a-IGZO) thin film transistors (V-TFTs) with 310 nm channel length were fabricated using a low temperature process (<300  °C), and their device performance was evaluated. The fabricated V-TFTs show well behaved transfer characteristics with an Ion/Ioff current ratio greater than 104 and a threshold voltage of 1.7 V. The influence of the vertical structure on device performance was analyzed in detail. In addition, current polarity characteristics that arise from different metal/a-IGZO contacts were also examined. The non-optimum performance of the V-TFTs was attributed to the fringing-field effect, high defect density, and large source/drain contact resistance.