Soft Recovery Process of Mechanically Degraded Flexible a-IGZO TFTs With Various Rolling Stresses and Defect Simulation Using TCAD Simulation

Kim, Beom-Su; Jeong, Hyun‐Jun; Han, Ki-Lim; Lee, Won-Bum; Kim, Yoon-Seo; Park, Jin‐Seong

doi:10.1109/ted.2019.2961119

Cited by 22 publications

(13 citation statements)

References 39 publications

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“…According to previous studies, mechanical stress can change the defect states in a-IGZO TFT. − And many studies have shown through TCAD simulation that bending stress increases both the Gaussian donor like state ( N GD ) and the Gaussian acceptor-like state ( N GA ) in a-IGZO TFT. − In these studies, the increase in N GD is explained by the formation of V o + /V o 2+ (ionized oxygen vacancy) states from some of neutral oxygen vacancy (V o ) states. And the increase in N GA is explicated by an increase in interstitial oxygen (O i ) states. ,, The generated V o + /V o 2+ state can contribute to the V th shift of negative direction by providing free electrons. The deep level O i state acts as an electron trap site and can become a degradation factor for SS.…”

Section: Results and Discussionmentioning

confidence: 99%

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Mechanical Durability of Flexible/Stretchable a-IGZO TFTs on PI Island for Wearable Electronic Application

Han

Lee

Kim

et al. 2021

ACS Appl. Electron. Mater.

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In this work, we examined the mechanical durability of island-type a-IGZO thin-film transistors (TFTs). Island TFTs were fabricated on polyimide (PI) islands and were transferred to a thermoplastic polyurethane (TPU) film. In repeated bending tests with a 1.5 mm bending radius, island TFTs showed less electrical property deterioration than TFTs on a PI film. We confirmed that the TPU, which has a lower elastic modulus compared to PI, effectively reduced the curvature of PI island even under the same bending test conditions. Furthermore, an organic passivation layer was applied on the upper part of the PI island. The 3 μm thick organic passivation layer made the TFT layer more stable against bending and elongation stress. Island TFTs with an organic passivation layer showed a change in the saturation mobility of only −2.3% and a change in the threshold voltage of −0.22 V even after 250 000 repetitive bending tests. Additionally, no change in electrical properties was observed even after 10 000 repeated stretching test cycles under 30% uniaxial elongation. Finally, we fabricated island-type logic circuits based on a-IGZO TFTs for wearable electronic applications. Using the organic passivation layer, we showed that the NMOS pseudoinverter and NAND gate also operated without significant deterioration in 100 000 repeated bending cycles and 5000 repeated stretching cycles. After applying repeated mechanical stresses, the high output voltage (V OH) and low output voltage (V OL) of the inverter only changed from 8.85 to 8.93 V and from 0.44 to 0.50 V, respectively. In NAND gates, V OH and V OL only changed slightly from 8.46 to 8.56 V and from 0.45 to 0.55 V, respectively.

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Section: Results and Discussionmentioning

confidence: 99%

“…And the increase in N GA is explicated by an increase in interstitial oxygen (O i ) states. 49,51,53 The generated V o + /V o 2+ state can contribute to the V th shift of negative direction by providing free electrons. The deep level O i state acts as an electron trap site and can become a degradation factor for SS.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Durability of Flexible/Stretchable a-IGZO TFTs on PI Island for Wearable Electronic Application

Han

Lee

Kim

et al. 2021

ACS Appl. Electron. Mater.

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“…The material properties are shown in Figure . [ 23,31,32 ] The fitting data and extracted DOS parameters are summarized in Figure S3 and Table S1 (Supporting Information), respectively. Figure 3a–d shows schematic energy band diagrams of single‐ and dual‐channel TFTs obtained using TCAD simulation to confirm the dual‐channel formation under V GS = 20 V. As the IZO thickness increases, the conduction band maximum (CBM) of IZO begins to band‐bend gradually below E f , forming a 2DEG‐like channel at the IZO layer.…”

Section: Resultsmentioning

confidence: 99%

Remarkable Stability Improvement with a High‐Performance PEALD‐IZO/IGZO Top‐Gate Thin‐Film Transistor via Modulating Dual‐Channel Effects

Kim

Lee

et al. 2022

Adv Materials Inter

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Plasma‐enhanced atomic layer deposition (PEALD)‐based bilayer IZO (back channel)/IGZO top‐gate thin‐film transistors (TFTs) with different IZO and IGZO layer thicknesses are fabricated to evaluate the correlation between thickness and electrical characteristics/reliability caused by dual‐channel modulation. The dual‐channel formed by IZO stacked on the backchannel improves both mobility and reliability of devices as the IZO layer thickness increases. In the TCAD simulation, as the thickness of IZO increases, the current flowing through the IZO channel among the dual channels increases and the main channel transition from IGZO to IZO occurs above a certain IZO layer thickness. The main channel transition to IZO, which has high mobility and is located in the backchannel away from the gate insulator (GI), leads to a mobility increase with a lower threshold voltage (Vth) shift and a remarkable improvement of reliability deteriorated by the GI. As a result, PEALD‐based IZO/IGZO TG TFTs exhibit both high mobility (≈40 cm2 V−1 s−1) and high stability (ΔVth = ‐0.07 V) of a positive bias temperature stress up to 10 800 s. This suggests that ALD‐based dual‐channel regulation by nanoscale thickness control of the stacking oxide semiconductor can overcome the trade‐off between mobility and reliability.

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“…The dielectric response of ferroelectrics can be analyzed from two aspects [16]: (1) Dielectric adjustability ;(2) Dielectric loss.…”

Section: Figure 1: Hysteresis Loop Of Ferroelectricsmentioning

confidence: 99%

PZT-based Antiferroelectric Material Based on Building Roof Film Rolling Process and Preparation Method Thereof

2021

IJETC

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Antiferroelectric material is a kind of ferroelectric material, which has been widely used in electronic equipment and construction industry. It has always been a research hotspot in the field of material science. In practical applications, the two main factors affecting its energy storage are polarization intensity and breakdown electric field. Due to the large thickness, poor internal consistency and low compression capacity, the energy storage function has not been improved. Therefore, this paper focuses on PZT based antiferroelectric materials based on building roof rolling process. At the same time, the relevant theories and various preparation methods of PZT antiferroelectric materials are introduced in detail. Finally, the solid-state reaction method is used to prepare PZT based antiferroelectric materials. The electrical properties of PZT based antiferroelectric materials were also studied. The experimental results show that the phase transition temperature at 100Hz is close to the theoretical value of 550K, and the test indexes are close to the theoretical value of PZT based antiferroelectric materials.

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Soft Recovery Process of Mechanically Degraded Flexible a-IGZO TFTs With Various Rolling Stresses and Defect Simulation Using TCAD Simulation

Cited by 22 publications

References 39 publications

Mechanical Durability of Flexible/Stretchable a-IGZO TFTs on PI Island for Wearable Electronic Application

Mechanical Durability of Flexible/Stretchable a-IGZO TFTs on PI Island for Wearable Electronic Application

Remarkable Stability Improvement with a High‐Performance PEALD‐IZO/IGZO Top‐Gate Thin‐Film Transistor via Modulating Dual‐Channel Effects

PZT-based Antiferroelectric Material Based on Building Roof Film Rolling Process and Preparation Method Thereof

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