Investigation of the Determining Factors for the “Mobility Boost” in High-k-Gated Transparent Oxide Semiconductor Thin-Film Transistors

Yuhang Sun; Junkyu Kim; Neel Chatterjee; Sarah L. Swisher

doi:10.1002/aelm.202001037

Investigation of the Determining Factors for the “Mobility Boost” in High-k-Gated Transparent Oxide Semiconductor Thin-Film Transistors

Yuhang Sun, Junkyu Kim, Neel Chatterjee, Sarah L. Swisher

Research output: Contribution to journal › Article › peer-review

Abstract

In metal-oxide thin-film transistors (TFTs), high-k gate dielectrics often yield a higher electron mobility than SiO₂. However, investigations regarding the mechanism of this high-k “mobility boost” are relatively scarce. To explore this phenomenon, solution-processed In₂O₃ TFTs are fabricated using eight different gate dielectrics (SiO₂, Al₂O₃, ZrO₂, HfO₂, and bilayer SiO₂/high-k structures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO₂-gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high-k gate dielectrics compared to SiO₂.

Original language	English (US)
Article number	2001037
Journal	Advanced Electronic Materials
Volume	7
Issue number	5
DOIs	https://doi.org/10.1002/aelm.202001037
State	Published - Mar 12 2021

Bibliographical note

Funding Information:
This material was based upon work supported by the National Science Foundation under Grant No. ECCS‐1710008, and through the University of Minnesota MRSEC under Award Number DMR‐2011401. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS‐2025124. The authors expressed their appreciation to Prof. Paul Ruden for his valuable guidance and constructive feedback while developing the device model.

Publisher Copyright:
© 2021 Wiley-VCH GmbH

Keywords

colloidal In O nanocrystals
field-effect mobility
high-k gate dielectrics
metal-oxide semiconductors
thin-film transistors

How much support was provided by MRSEC?

Partial

Reporting period for MRSEC

Period 1

Access

10.1002/aelm.202001037

Cite this

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title = "Investigation of the Determining Factors for the “Mobility Boost” in High-k-Gated Transparent Oxide Semiconductor Thin-Film Transistors",

abstract = "In metal-oxide thin-film transistors (TFTs), high-k gate dielectrics often yield a higher electron mobility than SiO2. However, investigations regarding the mechanism of this high-k “mobility boost” are relatively scarce. To explore this phenomenon, solution-processed In2O3 TFTs are fabricated using eight different gate dielectrics (SiO2, Al2O3, ZrO2, HfO2, and bilayer SiO2/high-k structures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO2-gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high-k gate dielectrics compared to SiO2.",

keywords = "colloidal In O nanocrystals, field-effect mobility, high-k gate dielectrics, metal-oxide semiconductors, thin-film transistors",

author = "Yuhang Sun and Junkyu Kim and Neel Chatterjee and Swisher, {Sarah L.}",

note = "Funding Information: This material was based upon work supported by the National Science Foundation under Grant No. ECCS‐1710008, and through the University of Minnesota MRSEC under Award Number DMR‐2011401. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS‐2025124. The authors expressed their appreciation to Prof. Paul Ruden for his valuable guidance and constructive feedback while developing the device model. Publisher Copyright: {\textcopyright} 2021 Wiley-VCH GmbH",

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AU - Swisher, Sarah L.

N1 - Funding Information: This material was based upon work supported by the National Science Foundation under Grant No. ECCS‐1710008, and through the University of Minnesota MRSEC under Award Number DMR‐2011401. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS‐2025124. The authors expressed their appreciation to Prof. Paul Ruden for his valuable guidance and constructive feedback while developing the device model. Publisher Copyright: © 2021 Wiley-VCH GmbH

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Y1 - 2021/3/12

N2 - In metal-oxide thin-film transistors (TFTs), high-k gate dielectrics often yield a higher electron mobility than SiO2. However, investigations regarding the mechanism of this high-k “mobility boost” are relatively scarce. To explore this phenomenon, solution-processed In2O3 TFTs are fabricated using eight different gate dielectrics (SiO2, Al2O3, ZrO2, HfO2, and bilayer SiO2/high-k structures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO2-gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high-k gate dielectrics compared to SiO2.

AB - In metal-oxide thin-film transistors (TFTs), high-k gate dielectrics often yield a higher electron mobility than SiO2. However, investigations regarding the mechanism of this high-k “mobility boost” are relatively scarce. To explore this phenomenon, solution-processed In2O3 TFTs are fabricated using eight different gate dielectrics (SiO2, Al2O3, ZrO2, HfO2, and bilayer SiO2/high-k structures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO2-gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high-k gate dielectrics compared to SiO2.

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Investigation of the Determining Factors for the “Mobility Boost” in High-k-Gated Transparent Oxide Semiconductor Thin-Film Transistors

Abstract

Bibliographical note

Keywords

How much support was provided by MRSEC?

Reporting period for MRSEC

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University of Minnesota Materials Research Science and Engineering Center (DMR-2011401)

Cite this

Investigation of the Determining Factors for the “Mobility Boost” in High-k-Gated Transparent Oxide Semiconductor Thin-Film Transistors

Abstract

Bibliographical note

Keywords

How much support was provided by MRSEC?

Reporting period for MRSEC

Access

Other files and links

Fingerprint

Projects

University of Minnesota Materials Research Science and Engineering Center (DMR-2011401)

Cite this