Electrical characteristics of flexible amorphous indium–tin–gallium–zinc oxide thin-film transistors under repetitive mechanical stress

Abstract

In this study, we investigated the effect of repetitive mechanical stress on the electrical characteristics of amorphous indium–tin–gallium–zinc oxide (a-ITGZO) thin-film transistors (TFTs). The degradation of the electrical characteristics of an a-ITGZO TFT with a curvature radius of 2 mm is minimal even after the TFT undergoes bending 105 times. Our technology computer-aided design simulation reveals that the electrical characteristics degraded by the repeated bending cycles are due to the increase in the acceptor-like Gaussian states (N GA) related with the generation of oxygen interstitial defects.

Flexible Oxide Thin Film Transistors, Memristors, and Their Integration

“…Although, there is no convention of how the flexibility is evaluated yet, the typical tests observed in the articles are mentioned in Section 2.2. Mechanical stability is crucial for flexible electronics, as devices need to maintain their performance during bending and stretching (Figure 4a) for applications in flexible displays, wearables, [51,80,81] etc. Bending machines are often used (Figure 4b), which either lock the substrate at opposite ends with clamps and press them inward [51,80,81] or it locks half of the substrate on a clamp and press downward or upward the other half, [82,83] or by fitting the substrate on a metal rod, [62] while the device is in operation.…”

“…A key obstacle in IGZO-based devices, is the presence of Indium in the compound as it is a rare element. In an effort to minimize Indium, the mixture of Indium Tin Gallium Zinc Oxide (ITGZO) [47,51] was proposed, which replaces part of Indium with Tin due to their compatibility of ions in terms of quantum number that directly impacts the conductive electron pathway. [113] Flexible ITGZO TFTs have been demonstrated on CPI films with excellent mobilities of 34.32 cm 2 V −1 s −1 and SS of 169 mV, with good electrical stability under bending to a 2 mm radius.…”

“…[113] Flexible ITGZO TFTs have been demonstrated on CPI films with excellent mobilities of 34.32 cm 2 V −1 s −1 and SS of 169 mV, with good electrical stability under bending to a 2 mm radius. [47] Lee et al, [47,51] reported ITGZO TFTs under repetitive mechanical stress and demonstrated robust electrical performance of ≈30 cm 2 V −1 s −1 below 50000 bending cycles.…”

“…Copyright 2017, IOP Publishing Ltd. h) CPI transparent layer undergoing a bending test of radius R = 2 mm. Reproduced with permission [51]. Copyright 2021, The Japan Society of Applied Physics.…”

Effect of dual gating on electrical characteristics of amorphous indium‐tin‐gallium‐zinc‐oxide TFTs

“…Considering that oxide transistors are promising for low-power electronic systems on paper [3,4], our study contributes to realization of high-performance oxide TFTs being essential for paper electronics. In this study, amorphous indium-tin-gallium-zinc-oxide (a-ITGZO) is chosen as a channel material; this oxide has emerged as a new channel material for high-performance oxide TFTs [15][16][17][18]. The effect of dual gating on the electrical characteristics is compared with those of top and bottom gating.…”