Device Performance Improvement of Transparent Thin-Film Transistors With a Ti-Doped GaZnO/InGaZnO/Ti-Doped GaZnO Sandwich Composite-Channel Structure

et al. 2021

Adv Elect Materials

An amorphous indium gallium zinc oxide (a‐IGZO) layer is deposited on very thin conductive amorphous indium zinc oxide (a‐IZO) thin film to demonstrate high‐performance, coplanar thin‐film transistors (TFTs) with dual‐channel oxide semiconductor architecture. Based on material properties, a conduction band offset (∆EC) of ≈0.28 eV between a‐IZO and a‐IGZO layers and a conduction band bending of ≈0.3 eV at a‐IGZO/gate insulator (GI) interface exist. Through the electrical characterization, high field‐effect mobility (μFE) of ≈50 cm2 V−1 s−1, a positive threshold voltage (VTh) of ≈2.3 V, and low off‐current (IOFF) of <1 pA in coplanar a‐IZO/a‐IGZO TFT are demonstrated. The electron accumulation (>5 × 1018 cm−3) at both the a‐IZO/a‐IGZO and a‐IGZO/GI interfaces confirm the dual‐channel conduction. The bottom a‐IZO channel significantly contributes to increasing drain current (ID) due to large electron density (≈1019 cm−3). The dual‐channel coplanar TFT with a‐IGZO/IZO provides a guideline for overcoming the trade‐off between high μFE and positive VTh control for stable enhancement mode operation with increased ID.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High‐Performance Coplanar Dual‐Channel a‐InGaZnO/a‐InZnO Semiconductor Thin‐Film Transistors with High Field‐Effect Mobility

Billah

Siddik

et al. 2021

Adv Elect Materials

“…[ 25 ] In addition, a titanium doping technique was suggested not only to increase the density of electrons in the IGZO channel but also to suppress defect formation. [ 26 ] However, this approach has been limited to channel doping. Another promising strategy is to insert an insulating buffer layer between the metal electrodes and the crystalline semiconductor to simultaneously improve channel and contact properties.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Role of Al₂O₃ Interlayer in Indium–Gallium–Zinc–Oxide Transistors

Physica Status Solidi (a)

Park

et al. 2021

Although insertion of a thin insulating layer between metal electrodes and a semiconducting channel is an effective way to improve device performance, the exact reason for improvement in performance is not elucidated. Herein, the role of an Al2O3 interlayer sandwiched between Al metal electrodes and an amorphous indium–gallium–zinc–oxide semiconducting channel is systematically investigated. The Al2O3 interlayer results in not only a good transistor performance with increased on current but also improved gate bias stress stability. The improvement is primarily attributed to a doping effect and mitigation of interface defects. Energy‐band diagrams, experimentally obtained from temperature‐variable electrical characterization and electrostatic force microscopy, validate the channel doping effect, which increase the tunneling probability of the electron charge carriers via a reduction of the Schottky barrier width. A comprehensive study on the influence of various processing parameters, including Al2O3 thickness, post‐annealing treatment conditions, and types of electrodes, on the transistor device is also performed. This approach guides the practical implementation of stable sol–gel oxide‐based thin‐film transistors and promotes integrated circuitry applications.

“…Transparent conductive electrodes (TCEs) are the core components of a variety of optoelectronic devices such as flexible displays, thin film transistors, solar cells, and touch screen panels . Among the different types of TCEs investigated, the oxide/metal/oxide (OMO) structured multilayer films are one of the most promising transparent conducting oxide (TCO) materials for applications requiring flexible TCEs; this is because of the excellent optical and electrical performance of these films in flexible TCEs, as well as their cost effectiveness .…”

Section: Introductionmentioning

confidence: 99%

Investigation of SiO₂/TiO₂ Index Matching Layer Applied to MTO/Ag/MTO Structured Film Deposited on PET Substrate

Yoon

Physica Status Solidi (a)

Jang

2018

For the commercial application of transparent conductive oxide (TCO) materials in touch screens, the incident light should be reflected at the interfaces between the stacked TCO layers having different refractive indices. To reduce optical loss, the presence of an index-matching (IM) passivation layer between the conductive layer and substrate is necessary. The objective of the present study is to evaluate and compare the effects of an IM layer (SiO 2 /TiO 2 ) on the optical spectra and color variation in the case of MTO/ Ag/MTO films with and without the SiO 2 /TiO 2 layers. The optical properties are systematically investigated using an ultraviolet (UV)-visible (Vis) spectrophotometer. The optical transmittance of all fabricated films is higher than 85% at the wavelength of 550 nm. The optimal thickness of the SiO 2 /TiO 2 layer is SiO 2 (90, 100 nm)/TiO 2 (10 nm). A low reflectance difference (ΔR 550nm ) of 1.5 and 1.3%, and the color difference representing the blueyellow color (Δb Ã ) of 0.6 and 3.1 are achieved with the optimal thickness of SiO 2 (90 and 100 nm)/TiO 2 (10 nm), respectively.