Understanding hydrogen and nitrogen doping on active defects in amorphous ln-Ga-Zn-O thin film transistors

摘要

This work analyses the physics of active trap states impacted by hydrogen (H) and nitrogen (N) dopings in amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) and investigates their effects on the device performances under back-gate biasing. Based on numerical simulation and interpretation of the device transfer characteristics, it is concluded that the interface and bulk tail states, as well as the 2thorn charge states (i.e., acceptors V-O(2+)) related to oxygen vacancy (V-O), are neutralized by the H/N dopants incorporation via an experimental plasma treatment. Moreover, the simulation reveals that an acceptor-like defect VOH has been induced by the H doping, to support the observed additional degradation of device subthreshold slope. Superior stability of the optimized a-IGZO TFTs under a proper amount of H/N doping is demonstrated by the decreased density of V-O-related defects in simulation, where hole (V-O(0) donor) and electron trapping (O-i acceptor) occurs during the negative or positive bias stresses. This work benefit lies in an in-depth systematic understanding and exploration of the effects of the incorporation of the H and N dopants into the a-IGZO film for the TFTs improvement and optimization. Published by AIP Publishing.