Interfacial AlN formation of Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors

Seonno Yoon, Jangwon Bang, Hi Deok Lee, Jungwoo Oh

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We report on the electrical and microstructural analysis on Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors grown on Si (111) substrate. With optimized Si and Ti thickness in Si/Ti/Al/Cu Ohmic metallization, a minimum Ohmic contact resistance of 0.44 Ω mm and specific contact resistance of 3 × 10- 6 -cm2 with smooth surface morphology were achieved. Significant change in electrical performance and morphology showed high dependence of Ti and Si thickness on the multilayer metal scheme. Importantly, refractory behavior was shown in low annealing temperature, though uniform and continuous TiSix with low work function was formed on AlGaN. However, Ohmic behavior was shown in high annealing temperature, because thin AIN surrounding TiN promotes further N vacancies in GaN than the conventional Ti/Al-based Ohmic contact does. An outer Cu layer has low resistivity and the interfacial Si layer forms TiSix, which works as only a barrier to prevent Cu in-diffusion, not to transport current. As a result, we revealed that Ohmic contact mechanism in Si/Ti/Al/Cu is governed mainly by field emission near the Fermi level or themionic-field emission. Microstructural study on metal/semiconductor interface region was conducted by using transmission electron microscopy (TEM).

Original languageEnglish
Pages (from-to)60-63
Number of pages4
JournalMicroelectronic Engineering
Volume151
DOIs
Publication statusPublished - 2016 Feb 5

Fingerprint

Ohmic contacts
High electron mobility transistors
high electron mobility transistors
electric contacts
contact resistance
field emission
Contact resistance
Field emission
annealing
Metals
refractories
Annealing
metals
Metallizing
Fermi level
Refractory materials
Vacancies
Surface morphology
Multilayers
transmission electron microscopy

All Science Journal Classification (ASJC) codes

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

Cite this

@article{648e01626941464586943688aa0ca052,
title = "Interfacial AlN formation of Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors",
abstract = "We report on the electrical and microstructural analysis on Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors grown on Si (111) substrate. With optimized Si and Ti thickness in Si/Ti/Al/Cu Ohmic metallization, a minimum Ohmic contact resistance of 0.44 Ω mm and specific contact resistance of 3 × 10- 6 -cm2 with smooth surface morphology were achieved. Significant change in electrical performance and morphology showed high dependence of Ti and Si thickness on the multilayer metal scheme. Importantly, refractory behavior was shown in low annealing temperature, though uniform and continuous TiSix with low work function was formed on AlGaN. However, Ohmic behavior was shown in high annealing temperature, because thin AIN surrounding TiN promotes further N vacancies in GaN than the conventional Ti/Al-based Ohmic contact does. An outer Cu layer has low resistivity and the interfacial Si layer forms TiSix, which works as only a barrier to prevent Cu in-diffusion, not to transport current. As a result, we revealed that Ohmic contact mechanism in Si/Ti/Al/Cu is governed mainly by field emission near the Fermi level or themionic-field emission. Microstructural study on metal/semiconductor interface region was conducted by using transmission electron microscopy (TEM).",
author = "Seonno Yoon and Jangwon Bang and Lee, {Hi Deok} and Jungwoo Oh",
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Interfacial AlN formation of Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors. / Yoon, Seonno; Bang, Jangwon; Lee, Hi Deok; Oh, Jungwoo.

In: Microelectronic Engineering, Vol. 151, 05.02.2016, p. 60-63.

Research output: Contribution to journalArticle

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T1 - Interfacial AlN formation of Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors

AU - Yoon, Seonno

AU - Bang, Jangwon

AU - Lee, Hi Deok

AU - Oh, Jungwoo

PY - 2016/2/5

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AB - We report on the electrical and microstructural analysis on Si/Ti/Al/Cu Ohmic contact for AlGaN/GaN high-electron-mobility transistors grown on Si (111) substrate. With optimized Si and Ti thickness in Si/Ti/Al/Cu Ohmic metallization, a minimum Ohmic contact resistance of 0.44 Ω mm and specific contact resistance of 3 × 10- 6 -cm2 with smooth surface morphology were achieved. Significant change in electrical performance and morphology showed high dependence of Ti and Si thickness on the multilayer metal scheme. Importantly, refractory behavior was shown in low annealing temperature, though uniform and continuous TiSix with low work function was formed on AlGaN. However, Ohmic behavior was shown in high annealing temperature, because thin AIN surrounding TiN promotes further N vacancies in GaN than the conventional Ti/Al-based Ohmic contact does. An outer Cu layer has low resistivity and the interfacial Si layer forms TiSix, which works as only a barrier to prevent Cu in-diffusion, not to transport current. As a result, we revealed that Ohmic contact mechanism in Si/Ti/Al/Cu is governed mainly by field emission near the Fermi level or themionic-field emission. Microstructural study on metal/semiconductor interface region was conducted by using transmission electron microscopy (TEM).

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