P‐4: TCAD Simulation of Hydrogen Diffusion Induced Bias Temperature Instability in a‐IGZO Thin‐Film Transistors

Abstract

Since the first introduction of amorphous IGZO TFTs, many researchers have investigated the temperature, bias, and luminous instability mechanisms of these devices. In this paper we have developed TCAD process and device models, including hydrogen diffusion and transport to explain degradation phenomena. Our approach has been validated using measurements data.

Defects in Amorphous Semiconductors: The Case of Amorphous Indium Gallium Zinc Oxide

“…This increase provides a thermodynamic drive to reduce the defect concentration, lessening the doping of the layer and shifting the transistor threshold voltage positively. This model for PBS is supported by recent technology computer-aided design (TCAD) simulations [19], showing a good fit of experimental transfer curves shift under PBS by considering a hydrogen diffusion process out of the channel layer.…”

“…The fundamental understanding of a-IGZO and the origin of its bias instabilities are still controversial due to the complexity of the amorphous nature of the material. For instance, the origin of PBS has been explained by a great many possible mechanisms: charge trapping processes occurring at the interfaces and/or in the dielectric [12,13], the creation of deep traps [12][13][14] in the semiconductor, the absorption of oxygen or water molecules at the channel interface [12,13,15], the removal of oxygen interstitials [15], the creation of undercoordinated cation pairs [16], the capture of electrons by oxygen vacancies [17], the reduction of peroxide concentration [18], and the diffusion of hydrogen [19,20].…”