Effect of interfacial InZnO conducting layer on electrical performance and bias stress stability of InAlZnO thin-film transistors

Woo, Kyoungwan; Lee, Se Hyeong; Lee, Sang‐Hyun; Bak, So-Young; Kim, Yoo-Jong; Yi, Moonsuk

doi:10.1016/j.mee.2019.111006

Cited by 12 publications

(1 citation statement)

References 13 publications

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“…Additionally, immediately within 0.1 s after a positive voltage pulse was applied to the gate (+30 V amplitude for 10 s), the number of carriers abruptly increased, converting the channel layer into a metallic state, as illustrated in the right panel of Figure 2a. For transistors based on oxides containing In, the switching behavior could not be accomplished because I D was maintained at a high constant value (i.e., a metallic state) owing to the high carrier density that originated from excessive defects, regardless of the magnitude of the gate voltage [27,28]. In such cases, it was impossible to convert the channel layer from the metallic state to the semiconducting state by external stimuli such as voltage and light pulses.…”

Section: Characteristics Of Mst Devicesmentioning

confidence: 99%

Synaptic Transistors Exhibiting Gate-Pulse-Driven, Metal-Semiconductor Transition of Conduction

et al. 2021

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Neuromorphic devices have been investigated extensively for technological breakthroughs that could eventually replace conventional semiconductor devices. In contrast to other neuromorphic devices, the device proposed in this paper utilizes deep trap interfaces between the channel layer and the charge-inducing dielectrics (CID). The device was fabricated using in-situ atomic layer deposition (ALD) for the sequential deposition of the CID and oxide semiconductors. Upon the application of a gate bias pulse, an abrupt change in conducting states was observed in the device from the semiconductor to the metal. Additionally, numerous intermediate states could be implemented based on the number of cycles. Furthermore, each state persisted for 10,000 s after the gate pulses were removed, demonstrating excellent synaptic properties of the long-term memory. Moreover, the variation of drain current with cycle number demonstrates the device’s excellent linearity and symmetry for excitatory and inhibitory behaviors when prepared on a glass substrate intended for transparent devices. The results, therefore, suggest that such unique synaptic devices with extremely stable and superior properties could replace conventional semiconducting devices in the future.

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Section: Characteristics Of Mst Devicesmentioning

confidence: 99%

Synaptic Transistors Exhibiting Gate-Pulse-Driven, Metal-Semiconductor Transition of Conduction

et al. 2021

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Optimal Aluminum Doping Method in PEALD for Designing Outstandingly Stable InAlZnO TFT

Woo

Cho

Park

2023

Adv Materials Inter

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In particular, the high mobility of oxide semiconductors compared to amorphous Si (a-Si) is suitable for achieving highresolution, high-driving frequency displays, and the amorphous phase of oxide semiconductors can solve the issues caused by grain boundaries, which is a fatal problem of low-temperature poly-Si (LTPS). [3][4][5][6] In addition, because oxide semiconductors have high back-end-ofline (BEOL) compatibility, research on their application in memory devices is also actively progressing. [7] The extremely low off-current of oxide semiconductors can improve the retention of dynamic random-access memory (DRAM) [8,9] by lowering the charge loss through the transistor, and oxide semiconductors exhibit good compatibility with various insulating layers, allowing them to be used as semiconductor materials for NAND flash [10,11] or ferroelectric random-access memory (FeRAM). [12] For these various applications of oxide semiconductors, it is important to understand the role of the elements in oxide semiconductors to optimize the characteristics of thin films and devices. In particular, the characteristics of the devices can vary dramatically depending on the ratio of the cations in the oxide semiconductors. In the case of InGaZnO (IGZO), a representative quaternary oxide semiconductor, the role of each cation composition is already known, and studies are being conducted to determine their optimal composition. [4,[13][14][15][16] In is known to form a path for electrons to move through a large sphere-shaped 5s orbital. [14] Therefore, as the composition ratio of In increases, mobility increases; however, stability can be degraded owing to weak bonding between In and O. Moreover, Zn contributes to the formation of a network of oxide semiconductors. Finally, Ga is known as a carrier suppressor and long-range stabilizer of IGZO. [1] Ga 3+ forms a stronger chemical bond with O 2− than with Zn 2+ or In 3+ ; therefore, the oxygen vacancy (V o ), which is one of the reasons for carrier formation and instability, can be suppressed. [17] However, several issues with IGZO arise from this Ga composition. For a carrier suppressor, the binding energy between Ga and O is weak, and IGZO has a relatively narrow band gap, which causes instability under illumination. [18,19] Additionally, inexpensive carrier suppressor elements that can replace relatively expensive Ga are required. From these points of view, research on InAlZnO (IAZO) using Al as a replacement element for Ga is being conducted. [20][21][22] Oxide semiconductors are promising semiconducting materials for next-generation thin-film transistors (TFTs). The role of the cations should be considered in the design of oxide semiconductors suitable for various applications. Ga has been widely used as a carrier suppressor in oxide semiconductors; however, research has recently been conducted to replace it with Al, which is cheaper and forms a stronger bond with O. Deposition using plasmaenhanced atomic layer deposition (PEALD) is very useful for controlling the composition of...

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Synergistically Enhanced Performance and Reliability of Abrupt Metal‐Oxide Heterojunction Transistor

Wang

Yang

et al. 2022

Adv Elect Materials

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The large‐area low‐temperature processing capability and versatile characteristics of amorphous oxide semiconductor (AOS) thin‐film transistors (TFTs) are highly expected to promote the developments of next‐generation displays, 3D integrated circuit (3DIC), flexible chips, and electronics. However, the abundant native defects in AOSs engrain an inherent trade‐off between high mobility and trustworthy stability in AOS TFTs, fundamentally limiting the performance metrics and integration scale of oxide‐based electronics. To surmount this obstacle, the bilayer AOS channel is highly expected to combine the merits of diversified AOSs, while the efficiency of such an AOS “heterojunction” is debatable. This work systematically compares the TFTs based on amorphous InGaZnO (a‐IGZO), amorphous InZnO (a‐IZO), and a‐IZO/a‐IGZO bilayer. The active cation interaction between metal‐oxide semiconductors gives rise to a mixed AOS layer rather than a heterojunction channel, corresponding to moderate performance metrics. Such a spontaneous cation interdiffusion is effectively prevented using a dense metal‐oxide dielectric interlayer, aluminum oxide (AlOx). The sharpened interface effectively forms an abrupt metal‐oxide heterojunction, while the electron can still tunnel through the ultrathin AlOx to create a quantum well of 2D electron gas (2DEG). The overall performance and reliability of multilayer AOS TFT are synergistically enhanced using the proposed abrupt metal‐oxide heterojunction architecture.

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Effect of interfacial InZnO conducting layer on electrical performance and bias stress stability of InAlZnO thin-film transistors

Cited by 12 publications

References 13 publications

Synaptic Transistors Exhibiting Gate-Pulse-Driven, Metal-Semiconductor Transition of Conduction

Synaptic Transistors Exhibiting Gate-Pulse-Driven, Metal-Semiconductor Transition of Conduction

Optimal Aluminum Doping Method in PEALD for Designing Outstandingly Stable InAlZnO TFT

Synergistically Enhanced Performance and Reliability of Abrupt Metal‐Oxide Heterojunction Transistor

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