Manipulation of polarization effect to engineer III-nitride HEMTs for normally-off operation

Yung Chi Yao, Chun Ying Huang, Tai Yuan Lin, Li Lien Cheng, Ching Yun Liu, Mei Tan Wang, Jung Min Hwang, Ya Ju Lee

Research output: Contribution to journalReview article

3 Citations (Scopus)

Abstract

We propose a novel, normally-off AlGaN/GaN high-electron-mobility transistor (HEMT) governed by polarization engineering. The fundamental concept is to grade the Al composition of the barrier layer from GaN to AlxGa1- xN, thereby alleviating the impact of piezoelectric polarization on the two-dimensional electron gas (2-DEG) and establishing a conduction-band profile well above the Fermi energy. These effects lead to a positive shift in the threshold voltage of the device and benefit the normally-off operation. It is observed that the device's DC transfer characteristics can be further modulated simply by adjusting the Al composition of the AlyGa1- yN cap layer and the p-type doping concentration at the top of the GaN buffer layer. These findings, based on a physical simulation of the proposed device, provide a guideline for the implementation of highly efficient, normally-off AlGaN/GaN HEMTs.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalMicroelectronic Engineering
Volume138
DOIs
Publication statusPublished - 2015 Apr 20

Fingerprint

High electron mobility transistors
high electron mobility transistors
Nitrides
engineers
nitrides
manipulators
Polarization
Engineers
Two dimensional electron gas
polarization
Buffer layers
Fermi level
Conduction bands
Chemical analysis
Threshold voltage
Doping (additives)
barrier layers
caps
threshold voltage
electron gas

Keywords

  • 2-DEG
  • AlGaN/GaN HEMT
  • DC transfer characteristics
  • Normally-off operation
  • Polarization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

Cite this

Manipulation of polarization effect to engineer III-nitride HEMTs for normally-off operation. / Yao, Yung Chi; Huang, Chun Ying; Lin, Tai Yuan; Cheng, Li Lien; Liu, Ching Yun; Wang, Mei Tan; Hwang, Jung Min; Lee, Ya Ju.

In: Microelectronic Engineering, Vol. 138, 20.04.2015, p. 1-6.

Research output: Contribution to journalReview article

Yao, Yung Chi ; Huang, Chun Ying ; Lin, Tai Yuan ; Cheng, Li Lien ; Liu, Ching Yun ; Wang, Mei Tan ; Hwang, Jung Min ; Lee, Ya Ju. / Manipulation of polarization effect to engineer III-nitride HEMTs for normally-off operation. In: Microelectronic Engineering. 2015 ; Vol. 138. pp. 1-6.
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abstract = "We propose a novel, normally-off AlGaN/GaN high-electron-mobility transistor (HEMT) governed by polarization engineering. The fundamental concept is to grade the Al composition of the barrier layer from GaN to AlxGa1- xN, thereby alleviating the impact of piezoelectric polarization on the two-dimensional electron gas (2-DEG) and establishing a conduction-band profile well above the Fermi energy. These effects lead to a positive shift in the threshold voltage of the device and benefit the normally-off operation. It is observed that the device's DC transfer characteristics can be further modulated simply by adjusting the Al composition of the AlyGa1- yN cap layer and the p-type doping concentration at the top of the GaN buffer layer. These findings, based on a physical simulation of the proposed device, provide a guideline for the implementation of highly efficient, normally-off AlGaN/GaN HEMTs.",
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AU - Yao, Yung Chi

AU - Huang, Chun Ying

AU - Lin, Tai Yuan

AU - Cheng, Li Lien

AU - Liu, Ching Yun

AU - Wang, Mei Tan

AU - Hwang, Jung Min

AU - Lee, Ya Ju

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N2 - We propose a novel, normally-off AlGaN/GaN high-electron-mobility transistor (HEMT) governed by polarization engineering. The fundamental concept is to grade the Al composition of the barrier layer from GaN to AlxGa1- xN, thereby alleviating the impact of piezoelectric polarization on the two-dimensional electron gas (2-DEG) and establishing a conduction-band profile well above the Fermi energy. These effects lead to a positive shift in the threshold voltage of the device and benefit the normally-off operation. It is observed that the device's DC transfer characteristics can be further modulated simply by adjusting the Al composition of the AlyGa1- yN cap layer and the p-type doping concentration at the top of the GaN buffer layer. These findings, based on a physical simulation of the proposed device, provide a guideline for the implementation of highly efficient, normally-off AlGaN/GaN HEMTs.

AB - We propose a novel, normally-off AlGaN/GaN high-electron-mobility transistor (HEMT) governed by polarization engineering. The fundamental concept is to grade the Al composition of the barrier layer from GaN to AlxGa1- xN, thereby alleviating the impact of piezoelectric polarization on the two-dimensional electron gas (2-DEG) and establishing a conduction-band profile well above the Fermi energy. These effects lead to a positive shift in the threshold voltage of the device and benefit the normally-off operation. It is observed that the device's DC transfer characteristics can be further modulated simply by adjusting the Al composition of the AlyGa1- yN cap layer and the p-type doping concentration at the top of the GaN buffer layer. These findings, based on a physical simulation of the proposed device, provide a guideline for the implementation of highly efficient, normally-off AlGaN/GaN HEMTs.

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