Molecular beam epitaxy of In-assisted ScAlN/GaN HEMT structures with ultralow sheet resistance

Liuyun Yang; Haotian Ye; Jinlin Wang; Ding Wang; Bingxuan An; Tao Wang; Rui Wang; Fang Liu; Bowen Sheng; Weikun Ge; Ping Wang; Xinqiang Wang

doi:10.1063/5.0283382

Molecular beam epitaxy of In-assisted ScAlN/GaN HEMT structures with ultralow sheet resistance

Liuyun Yang, Haotian Ye, Jinlin Wang, Ding Wang, Bingxuan An, Tao Wang, Rui Wang, Fang Liu, Bowen Sheng, Weikun Ge, Ping Wang^*, Xinqiang Wang^*

^*Corresponding author for this work

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

Abstract

ScAlN, featuring bipolar switchable spontaneous polarization along with enhanced piezoelectricity and electromechanical coupling coefficients, emerges as a highly promising ultrawide bandgap semiconductor for next-generation high-power and high-frequency electronic applications. In this work, we demonstrate an ultralow sheet resistance two-dimensional electron gas (2DEG) in ScAlN-based high electron mobility transistor (HEMT) structures, grown on sapphire substrates via molecular beam epitaxy. By employing indium (In) as a surfactant and introducing an ultrathin AlN interlayer to engineer a sharp interface, we achieve a sheet resistance of 137 Ω/□, with an electron mobility of 1020 cm²/V·s and a sheet electron density of 4.5 × 10¹³ cm⁻². The realization of ultralow sheet resistance in ScAlN/GaN heterostructures paves the way for advancements in microwave and radio frequency device technologies.

Original language	English
Article number	152101
Journal	Applied Physics Letters
Volume	127
Issue number	15
DOIs	https://doi.org/10.1063/5.0283382
Publication status	Published - 13 Oct 2025
Externally published	Yes

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© 2025 Author(s).

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@article{19b51df5578b4b50ae6e92cbded6633d,

title = "Molecular beam epitaxy of In-assisted ScAlN/GaN HEMT structures with ultralow sheet resistance",

abstract = "ScAlN, featuring bipolar switchable spontaneous polarization along with enhanced piezoelectricity and electromechanical coupling coefficients, emerges as a highly promising ultrawide bandgap semiconductor for next-generation high-power and high-frequency electronic applications. In this work, we demonstrate an ultralow sheet resistance two-dimensional electron gas (2DEG) in ScAlN-based high electron mobility transistor (HEMT) structures, grown on sapphire substrates via molecular beam epitaxy. By employing indium (In) as a surfactant and introducing an ultrathin AlN interlayer to engineer a sharp interface, we achieve a sheet resistance of 137 Ω/□, with an electron mobility of 1020 cm2/V·s and a sheet electron density of 4.5 × 1013 cm−2. The realization of ultralow sheet resistance in ScAlN/GaN heterostructures paves the way for advancements in microwave and radio frequency device technologies.",

author = "Liuyun Yang and Haotian Ye and Jinlin Wang and Ding Wang and Bingxuan An and Tao Wang and Rui Wang and Fang Liu and Bowen Sheng and Weikun Ge and Ping Wang and Xinqiang Wang",

note = "Publisher Copyright: {\textcopyright} 2025 Author(s).",

year = "2025",

month = oct,

day = "13",

doi = "10.1063/5.0283382",

language = "English",

volume = "127",

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TY - JOUR

T1 - Molecular beam epitaxy of In-assisted ScAlN/GaN HEMT structures with ultralow sheet resistance

AU - Yang, Liuyun

AU - Ye, Haotian

AU - Wang, Jinlin

AU - Wang, Ding

AU - An, Bingxuan

AU - Wang, Tao

AU - Wang, Rui

AU - Liu, Fang

AU - Sheng, Bowen

AU - Ge, Weikun

AU - Wang, Ping

AU - Wang, Xinqiang

PY - 2025/10/13

Y1 - 2025/10/13

N2 - ScAlN, featuring bipolar switchable spontaneous polarization along with enhanced piezoelectricity and electromechanical coupling coefficients, emerges as a highly promising ultrawide bandgap semiconductor for next-generation high-power and high-frequency electronic applications. In this work, we demonstrate an ultralow sheet resistance two-dimensional electron gas (2DEG) in ScAlN-based high electron mobility transistor (HEMT) structures, grown on sapphire substrates via molecular beam epitaxy. By employing indium (In) as a surfactant and introducing an ultrathin AlN interlayer to engineer a sharp interface, we achieve a sheet resistance of 137 Ω/□, with an electron mobility of 1020 cm2/V·s and a sheet electron density of 4.5 × 1013 cm−2. The realization of ultralow sheet resistance in ScAlN/GaN heterostructures paves the way for advancements in microwave and radio frequency device technologies.

AB - ScAlN, featuring bipolar switchable spontaneous polarization along with enhanced piezoelectricity and electromechanical coupling coefficients, emerges as a highly promising ultrawide bandgap semiconductor for next-generation high-power and high-frequency electronic applications. In this work, we demonstrate an ultralow sheet resistance two-dimensional electron gas (2DEG) in ScAlN-based high electron mobility transistor (HEMT) structures, grown on sapphire substrates via molecular beam epitaxy. By employing indium (In) as a surfactant and introducing an ultrathin AlN interlayer to engineer a sharp interface, we achieve a sheet resistance of 137 Ω/□, with an electron mobility of 1020 cm2/V·s and a sheet electron density of 4.5 × 1013 cm−2. The realization of ultralow sheet resistance in ScAlN/GaN heterostructures paves the way for advancements in microwave and radio frequency device technologies.

UR - https://www.scopus.com/pages/publications/105018578574

U2 - 10.1063/5.0283382

DO - 10.1063/5.0283382

M3 - Journal Article

AN - SCOPUS:105018578574

SN - 0003-6951

VL - 127

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 15

M1 - 152101

ER -

Molecular beam epitaxy of In-assisted ScAlN/GaN HEMT structures with ultralow sheet resistance

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