Growth of highly conductive Al-rich AlGaN:Si with low group-III vacancy concentration

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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2021-09-01

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en

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8

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AIP ADVANCES, Volume 11, issue 9

Abstract

The impact of AlGaN growth conditions on AlGaN:Si resistivity and surface morphology has been investigated using metalorganic chemical vapor deposition. Growth parameters including growth temperature, growth rate, and trimethylindium (TMI) flow have been systematically studied to minimize the resistivity of AlGaN:Si. We observed a strong anticorrelation between AlGaN:Si conductivity and growth temperature, suggesting increased silicon donor compensation at elevated temperatures. Secondary ion mass spectrometry and positron annihilation spectroscopy ruled out compensation by common impurities or group-III monovacancies as a reason for the observed phenomenon, in contrast to theoretical predictions. The underlying reason for AlGaN:Si resistivity dependence on growth temperature is discussed based on the possibility of silicon acting as a DX center in Al0.65Ga0.35N at high growth temperatures. We also show remarkable enhancement of AlGaN:Si conductivity by introducing TMI flow during growth. A minimum resistivity of 7.5 mΩ cm was obtained for n-type Al0.65Ga0.35N, which is among the lowest reported resistivity for this composition.

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Funding Information: This work was funded by the KACST-KAUST-UCSB Technology transfer program and the Solid State Lighting and Energy Electronics Center (SSLEEC) at UC Santa Barbara; a part of this work was carried out in the California NanoSystems Institute at UCSB. The research reported here made use of shared facilities of the UCSB MRSEC (Grant No. NSF DMR 1720256). A portion of this research was conducted in the UCSB nanofabrication facility, NSF NNIN network (Grant No. ECS-0335765). This work was partially funded by the Academy of Finland, Project No. 315082. The authors would like to gratefully thank Dr. Tom Mates for SIMS measurements and Dr. Stacia Keller and Dr. Mohammed Abo Alreesh for their insightful inputs. In addition, the authors would like to thank Dr. Youli Li from MRL and the cleanroom staff at the UCSB nanofabrication facility for the technical support provided. Publisher Copyright: © 2021 Author(s).

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Almogbel, A S, Zollner, C J, Saifaddin, B K, Iza, M, Wang, J, Yao, Y, Wang, M, Foronda, H, Prozheev, I, Tuomisto, F, Albadri, A, Nakamura, S, DenBaars, S P & Speck, J S 2021, ' Growth of highly conductive Al-rich AlGaN:Si with low group-III vacancy concentration ', AIP Advances, vol. 11, no. 9, 095119 . https://doi.org/10.1063/5.0066652