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

doi:10.1016/j.mee.2015.12.005

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

School of Integrated Technology

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

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 TiSi_x 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 TiSi_x, 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 language	English
Pages (from-to)	60-63
Number of pages	4
Journal	Microelectronic Engineering
Volume	151
DOIs	https://doi.org/10.1016/j.mee.2015.12.005
Publication status	Published - 2016 Feb 5

Bibliographical note

Funding Information:
This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The development of epi-growth analysis for next generation semiconductor and power semiconductor fundamental technology”); the Future Semiconductor Device Technology Development Program ( 10048536 ) funded by MOTIE and KSRC ; and the MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA.

Publisher Copyright:
© 2015 Published by Elsevier B.V.

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

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10.1016/j.mee.2015.12.005

Cite this

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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",

note = "Funding Information: This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The development of epi-growth analysis for next generation semiconductor and power semiconductor fundamental technology”); the Future Semiconductor Device Technology Development Program ( 10048536 ) funded by MOTIE and KSRC ; and the MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA. Publisher Copyright: {\textcopyright} 2015 Published by Elsevier B.V.",

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AU - Yoon, Seonno

AU - Bang, Jangwon

AU - Lee, Hi Deok

AU - Oh, Jungwoo

N1 - Funding Information: This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The development of epi-growth analysis for next generation semiconductor and power semiconductor fundamental technology”); the Future Semiconductor Device Technology Development Program ( 10048536 ) funded by MOTIE and KSRC ; and the MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA. Publisher Copyright: © 2015 Published by Elsevier B.V.

PY - 2016/2/5

Y1 - 2016/2/5

N2 - 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).

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

Abstract

Bibliographical note

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