Physical Modeling on Effective Traps Density Near the Conduction Band Dependence of Electrical Characteristics of Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors

Abstract

An (a-IGZO TFT) is modeled through experimental-based (a-IGZO TFTs) using (TCAD) simulator. A parametric study is performed on the numerical fit of the designed (a-IGZO TFT) current–voltage (I/V) characteristics, to obtain the near conduction band defects parameters optimal values, and to investigate the effect of the near band defects caused by oxygen vacancies on the (a-IGZO TFTs) output parameters. A new model approach is proposed for simulating (a-IGZO) electrical properties. The proposed model is known as a density of state models (DOS), and it is composed of two principal components, conduction band tail $$\left( {g_{ct}^{A} \left( E \right)} \right)$$ and Gaussian distributed donor-like $$\left( {g_{G}^{D} \left( E \right)} \right)$$ . The study of the presented (DOS) models is based on both conduction band tail elements that are known as tail acceptor density ( $$g_{ta}$$ ) as well as tail acceptor energy ( $$E_{a}$$ ), and Gaussian distributed donor-like elements which are donor gaussian energy ( $$E_{D}$$ ) and donor gaussian distribution ( $$g_{gd}$$ ). Results show that the tail acceptor states defects ( $$g_{ta}$$ , $$E_{a}$$ ) near the conduction band is the cause of the mobility and gaussian donor distribution degradation near the conduction band, and it has a major impact on changes that occur in the subthreshold region data [threshold voltage (Vth), subthreshold swing (SS), and on-state/off-states current ratio (Ion/Ioff)].