Numerical Analysis of Oxygen-Related Defects in Amorphous In-W-O Nanosheet Thin-Film Transistor

Abstract

The integration of 4 nm thick amorphous indium tungsten oxide (a-IWO) and a hafnium oxide (HfO2) high-κ gate dielectric has been demonstrated previously as one of promising amorphous oxide semiconductor (AOS) thin-film transistors (TFTs). In this study, the more positive threshold voltage shift (∆VTH) and reduced ION were observed when increasing the oxygen ratio during a-IWO deposition. Through simple material measurements and Technology Computer Aided Design (TCAD) analysis, the distinct correlation between different chemical species and the corresponding bulk and interface density of states (DOS) parameters were systematically deduced, validating the proposed physical mechanisms with a quantum model for a-IWO nanosheet TFT. The effects of oxygen flow on oxygen interstitial (Oi) defects were numerically proved for modulating bulk dopant concentration Nd and interface density of Gaussian acceptor trap NGA at the front channel, significantly dominating the transfer characteristics of a-IWO TFT. Furthermore, based on the studies of density functional theory (DFT) for the correlation between formation energy Ef of Oi defect and Fermi level (EF) position, we propose a numerical methodology for monitoring the possible concentration distribution of Oi as a function of a bias condition for AOS TFTs.

Atomic layer deposition for nanoscale oxide semiconductor thin film transistors: review and outlook

“…To achieve high stability, dopants such as Zr (Zr-In-Zn-O) [8], Hf (Hf-In-Zn-O) [9], and Si (Si-In-Zn-O) [10] have been suggested. Small amounts of W doping have also been introduced to suppress V o and achieve high stability using the high tungsten-oxide bond-dissociation energy in the In 2 O 3 matrix (In-W-O) [11,12]. Fabrication of crystalline oxide semiconductors was also explored to enhance electrical performance.…”

High-Performance Amorphous InGaSnO Thin-Film Transistor with ZrAlOx Gate Insulator by Spray Pyrolysis

“…Nowadays, there is increasing interest in amorphous metal oxide semiconductor (MOS) thin-film transistors (TFTs) to replace silicon-based TFTs [1][2][3][4][5]. Wide bandgap MOSs, such as zinc oxide (ZnO), amorphous indium gallium zinc oxide (a-IGZO), and amorphous indium tin zinc oxide (a-ITZO), are widely studied for high-performance TFT [1][2][3][4][5][6]. The metal oxide TFTs can be manufactured via vacuum [1] or solution process [7][8][9][10][11][12].…”

Thermal quenching of self-trapped exciton luminescence in nanostructured hafnia

“…Currently, the use of solid-state HfO 2 -based structures has good prospects for production of radiation-resistant and optically active coatings, for replacement of SiO 2 in CMOS transistor gates, and for creation of hardware components for new generation nanoelectronics [1][2][3][4][5][6][7][8]. Due to its high density and high atomic mass, nanostructured hafnium dioxide is also necessary in designing up-to-date scintillation media doped with various rare earth ions [9,10].…”