Polarization Effects of GaN and AlGaN

Polarization Bound Charge, Band Bending, and Electronic Surface States

Brianna S. Eller, Jialing Yang, Robert Nemanich

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

GaN-based devices are currently limited by reliability issues such as gate leakage and current collapse, where the mechanisms responsible for degradation are closely related to the electronic surface state configuration. Therefore, understanding the electronic surface state configuration of GaN-based materials will help improve device performance. Since GaN has an inherent polarization, these materials are also subject to a bound polarization charge, which influences the electronic state configuration. In this study, the surface band bending of N-face GaN, Ga-face GaN, and Ga-face AlGaN was measured with x-ray photoemission spectroscopy after various cleaning steps to investigate the effects of the polarization. Despite the different surface bound charge on these materials, similar band bending was observed regardless of the magnitude or direction of the charge. Specifically, the band bending varied from −0.1 eV to 0.9 eV on these samples, which supported the models of a Fermi level pinning state at ∼0.4 eV to 0.8 eV below the conduction band. Based on available literature, we suggest this pinning state is indirectly evident of a nitrogen vacancy or gallium-dangling bond.

Original languageEnglish (US)
Pages (from-to)4560-4568
Number of pages9
JournalJournal of Electronic Materials
Volume43
Issue number12
DOIs
StatePublished - 2014

Fingerprint

Surface states
Polarization
polarization
electronics
Gallium
Dangling bonds
configurations
Electronic states
Photoelectron spectroscopy
Fermi level
Conduction bands
Vacancies
Cleaning
Nitrogen
cleaning
gallium
Degradation
X rays
conduction bands
leakage

Keywords

  • AlGaN
  • band bending
  • GaN
  • polarization
  • surface states

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry

Cite this

Polarization Effects of GaN and AlGaN : Polarization Bound Charge, Band Bending, and Electronic Surface States. / Eller, Brianna S.; Yang, Jialing; Nemanich, Robert.

In: Journal of Electronic Materials, Vol. 43, No. 12, 2014, p. 4560-4568.

Research output: Contribution to journalArticle

@article{bf34eac43dc34f6782065bb03fd35900,
title = "Polarization Effects of GaN and AlGaN: Polarization Bound Charge, Band Bending, and Electronic Surface States",
abstract = "GaN-based devices are currently limited by reliability issues such as gate leakage and current collapse, where the mechanisms responsible for degradation are closely related to the electronic surface state configuration. Therefore, understanding the electronic surface state configuration of GaN-based materials will help improve device performance. Since GaN has an inherent polarization, these materials are also subject to a bound polarization charge, which influences the electronic state configuration. In this study, the surface band bending of N-face GaN, Ga-face GaN, and Ga-face AlGaN was measured with x-ray photoemission spectroscopy after various cleaning steps to investigate the effects of the polarization. Despite the different surface bound charge on these materials, similar band bending was observed regardless of the magnitude or direction of the charge. Specifically, the band bending varied from −0.1 eV to 0.9 eV on these samples, which supported the models of a Fermi level pinning state at ∼0.4 eV to 0.8 eV below the conduction band. Based on available literature, we suggest this pinning state is indirectly evident of a nitrogen vacancy or gallium-dangling bond.",
keywords = "AlGaN, band bending, GaN, polarization, surface states",
author = "Eller, {Brianna S.} and Jialing Yang and Robert Nemanich",
year = "2014",
doi = "10.1007/s11664-014-3383-z",
language = "English (US)",
volume = "43",
pages = "4560--4568",
journal = "Journal of Electronic Materials",
issn = "0361-5235",
publisher = "Springer New York",
number = "12",

}

TY - JOUR

T1 - Polarization Effects of GaN and AlGaN

T2 - Polarization Bound Charge, Band Bending, and Electronic Surface States

AU - Eller, Brianna S.

AU - Yang, Jialing

AU - Nemanich, Robert

PY - 2014

Y1 - 2014

N2 - GaN-based devices are currently limited by reliability issues such as gate leakage and current collapse, where the mechanisms responsible for degradation are closely related to the electronic surface state configuration. Therefore, understanding the electronic surface state configuration of GaN-based materials will help improve device performance. Since GaN has an inherent polarization, these materials are also subject to a bound polarization charge, which influences the electronic state configuration. In this study, the surface band bending of N-face GaN, Ga-face GaN, and Ga-face AlGaN was measured with x-ray photoemission spectroscopy after various cleaning steps to investigate the effects of the polarization. Despite the different surface bound charge on these materials, similar band bending was observed regardless of the magnitude or direction of the charge. Specifically, the band bending varied from −0.1 eV to 0.9 eV on these samples, which supported the models of a Fermi level pinning state at ∼0.4 eV to 0.8 eV below the conduction band. Based on available literature, we suggest this pinning state is indirectly evident of a nitrogen vacancy or gallium-dangling bond.

AB - GaN-based devices are currently limited by reliability issues such as gate leakage and current collapse, where the mechanisms responsible for degradation are closely related to the electronic surface state configuration. Therefore, understanding the electronic surface state configuration of GaN-based materials will help improve device performance. Since GaN has an inherent polarization, these materials are also subject to a bound polarization charge, which influences the electronic state configuration. In this study, the surface band bending of N-face GaN, Ga-face GaN, and Ga-face AlGaN was measured with x-ray photoemission spectroscopy after various cleaning steps to investigate the effects of the polarization. Despite the different surface bound charge on these materials, similar band bending was observed regardless of the magnitude or direction of the charge. Specifically, the band bending varied from −0.1 eV to 0.9 eV on these samples, which supported the models of a Fermi level pinning state at ∼0.4 eV to 0.8 eV below the conduction band. Based on available literature, we suggest this pinning state is indirectly evident of a nitrogen vacancy or gallium-dangling bond.

KW - AlGaN

KW - band bending

KW - GaN

KW - polarization

KW - surface states

UR - http://www.scopus.com/inward/record.url?scp=84919949410&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84919949410&partnerID=8YFLogxK

U2 - 10.1007/s11664-014-3383-z

DO - 10.1007/s11664-014-3383-z

M3 - Article

VL - 43

SP - 4560

EP - 4568

JO - Journal of Electronic Materials

JF - Journal of Electronic Materials

SN - 0361-5235

IS - 12

ER -