Numerical Study of Sub-Gap Density of States Dependent Electrical Characteristics in Amorphous In-Ga-Zn-O Thin-Film Transistors

Do-Kyung Kim,Xue Zhang,Jihwan Park,Jaehoon Park,Jin-Hyuk Bae

doi:10.3390/electronics9101652

Abstract

We demonstrate the effect of the sub-gap density of states (DOS) on electrical characteristics in amorphous indium-gallium-zinc (IGZO) thin-film transistors (TFTs). Numerical analysis based on a two-dimensional device simulator Atlas controlled the sub-gap DOS parameters such as tail acceptor-like states, tail donor-like states, Gauss acceptor-like states, and Gauss donor-like states in amorphous IGZO TFTs. We confirm accuracy by exploiting physical factors, such as oxygen vacancy, peroxide, hydrogen complex, band-to-band tunneling, and trap-assisted tunneling. Consequently, the principal electrical parameters, such as the threshold voltage, saturation mobility, sub-threshold swing, and on-off current ratio, are effectively tuned by controlling sub-gap DOS distribution in a-IGZO TFTs.

Highlights

Thin-film transistors (TFTs) have received significant attention because of the rapid development of displays, sensors, computing, radiofrequency tags, and analog signal processing [1,2,3,4,5,6]
Among the various next-generation material-based TFTs, amorphous oxide semiconductor (AOS) TFTs based on multi-components exhibit high uniformity because of their high mobility, amorphous phase, and high transparency and flexibility [11,12,13]
For the AOS IGZO TFT simulation, bottom-gate structure was used in this study (Figure 1a)

Summary

Introduction

Thin-film transistors (TFTs) have received significant attention because of the rapid development of displays, sensors, computing, radiofrequency tags, and analog signal processing [1,2,3,4,5,6]. We controlled sub-gap DOS distribution in variables such as tail acceptor-like states Sub-gap DOS distribution in variables such as tail states of electrical parameters, such as the threshold voltage Where E is the electron energy, EC is the conduction band edge energy, NTA is the sub-gap DOS at

Results

Conclusion