Analysis for Extremely Low Off-State Current in CAAC-IGZO FETs

摘要

A field effect transistor (FET) using c-axis aligned crystalline In-Ga-Zn-O (CAAC-IGZO) for an active layer has an extremely low off-state current, which is much lower than an off-state current of a silicon FET. As we measured and analyzed the off-state current, the voltage drop caused by the off-state current in a memory device was found to approach to a stretched exponential function. This is because in the off-state CAAC-IGZO FET, a small number of carriers move discretely and current does not flow uniformly. The low off-state current was also maintained even when its channel length was scaled down to approximately 50 nm.