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Title: Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO{sub 2} grown by atomic layer deposition

Abstract

The effect of post-deposition annealing on chemical bonding states at interface between Al{sub 0.5}Ga{sub 0.5}N and ZrO{sub 2} grown by atomic layer deposition (ALD) is studied by angle-resolved x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that both of Al-O/Al 2p and Ga-O/Ga 3d area ratio decrease at annealing temperatures lower than 500 °C, which could be attributed to “clean up” effect of ALD-ZrO{sub 2} on AlGaN. Compared to Ga spectra, a much larger decrease in Al-O/Al 2p ratio at a smaller take-off angle θ is observed, which indicates higher effectiveness of the passivation of Al-O bond than Ga-O bond through “clean up” effect near the interface. However, degradation of ZrO{sub 2}/AlGaN interface quality due to re-oxidation at higher annealing temperature (>500 °C) is also found. The XPS spectra clearly reveal that Al atoms at ZrO{sub 2}/AlGaN interface are easier to get oxidized as compared with Ga atoms.

Authors:
; ; ; ;  [1];  [1];  [2]; ;  [3];  [4]
  1. Novitas, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)
  2. (Singapore)
  3. Data Storage Institute, Agency for Science Technology and Research (A-STAR), 5 Engineering Drive 1, 117608 (Singapore)
  4. Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602 (Singapore)
Publication Date:
OSTI Identifier:
22412747
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM COMPOUNDS; ANNEALING; CHEMICAL BONDS; COMPARATIVE EVALUATIONS; DEPOSITION; GALLIUM NITRIDES; INTERFACES; OXIDATION; PASSIVATION; RESOLUTION; TRANSMISSION ELECTRON MICROSCOPY; X-RAY PHOTOELECTRON SPECTROSCOPY; ZIRCONIUM OXIDES

Citation Formats

Ye, Gang, Arulkumaran, Subramaniam, Ng, Geok Ing, Li, Yang, Ang, Kian Siong, Wang, Hong, E-mail: ewanghong@ntu.edu.sg, CINTRA CNRS/NTU/Thales, UMI 3288, 50 Nanyang Drive, Ng, Serene Lay Geok, Ji, Rong, and Liu, Zhi Hong. Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO{sub 2} grown by atomic layer deposition. United States: N. p., 2015. Web. doi:10.1063/1.4914351.
Ye, Gang, Arulkumaran, Subramaniam, Ng, Geok Ing, Li, Yang, Ang, Kian Siong, Wang, Hong, E-mail: ewanghong@ntu.edu.sg, CINTRA CNRS/NTU/Thales, UMI 3288, 50 Nanyang Drive, Ng, Serene Lay Geok, Ji, Rong, & Liu, Zhi Hong. Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO{sub 2} grown by atomic layer deposition. United States. doi:10.1063/1.4914351.
Ye, Gang, Arulkumaran, Subramaniam, Ng, Geok Ing, Li, Yang, Ang, Kian Siong, Wang, Hong, E-mail: ewanghong@ntu.edu.sg, CINTRA CNRS/NTU/Thales, UMI 3288, 50 Nanyang Drive, Ng, Serene Lay Geok, Ji, Rong, and Liu, Zhi Hong. 2015. "Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO{sub 2} grown by atomic layer deposition". United States. doi:10.1063/1.4914351.
@article{osti_22412747,
title = {Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO{sub 2} grown by atomic layer deposition},
author = {Ye, Gang and Arulkumaran, Subramaniam and Ng, Geok Ing and Li, Yang and Ang, Kian Siong and Wang, Hong, E-mail: ewanghong@ntu.edu.sg and CINTRA CNRS/NTU/Thales, UMI 3288, 50 Nanyang Drive and Ng, Serene Lay Geok and Ji, Rong and Liu, Zhi Hong},
abstractNote = {The effect of post-deposition annealing on chemical bonding states at interface between Al{sub 0.5}Ga{sub 0.5}N and ZrO{sub 2} grown by atomic layer deposition (ALD) is studied by angle-resolved x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that both of Al-O/Al 2p and Ga-O/Ga 3d area ratio decrease at annealing temperatures lower than 500 °C, which could be attributed to “clean up” effect of ALD-ZrO{sub 2} on AlGaN. Compared to Ga spectra, a much larger decrease in Al-O/Al 2p ratio at a smaller take-off angle θ is observed, which indicates higher effectiveness of the passivation of Al-O bond than Ga-O bond through “clean up” effect near the interface. However, degradation of ZrO{sub 2}/AlGaN interface quality due to re-oxidation at higher annealing temperature (>500 °C) is also found. The XPS spectra clearly reveal that Al atoms at ZrO{sub 2}/AlGaN interface are easier to get oxidized as compared with Ga atoms.},
doi = {10.1063/1.4914351},
journal = {Applied Physics Letters},
number = 9,
volume = 106,
place = {United States},
year = 2015,
month = 3
}
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  • Many dielectrics have been proposed for the gate stack or passivation of AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors, to reduce gate leakage and current collapse, both for power and RF applications. Atomic Layer Deposition (ALD) is preferred for dielectric deposition as it provides uniform, conformal, and high quality films with precise monolayer control of film thickness. Identification of the optimum ALD dielectric for the gate stack or passivation requires a critical investigation of traps created at the dielectric/AlGaN interface. In this work, a pulsed-IV traps characterization method has been used for accurate characterization of interface traps withmore » a variety of ALD dielectrics. High-k dielectrics (HfO{sub 2}, HfAlO, and Al{sub 2}O{sub 3}) are found to host a high density of interface traps with AlGaN. In contrast, ALD SiO{sub 2} shows the lowest interface trap density (<2 × 10{sup 12 }cm{sup −2}) after annealing above 600 °C in N{sub 2} for 60 s. The trend in observed trap densities is subsequently explained with bonding constraint theory, which predicts a high density of interface traps due to a higher coordination state and bond strain in high-k dielectrics.« less
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