A comparative study on device degradation under a positive gate stress and hot carrier stress in InGaZnO thin film transistors

摘要

The device degradations under a positive gate stress and hot carrier stress in InGaZnO thin film transistors have been compared experimentally. After hot carrier stress, the transfer curves were shifted positively just like after a positive gate stress, and thus the threshold voltage was increased. The increase of the threshold voltage is more significant after hot carrier stress than a positive gate stress. The recovery experiment proves that the increase of the threshold voltage after hot carrier stress is due to the electron trapped charges in the gate dielectrics. The threshold voltage shifts were enhanced for narrow devices under a positive gate stress and hot carrier stress. One can predict the device degradation by monitoring the gate current.