Molecular beam homoepitaxy of N-polar AlN: Enabling role of aluminum-assisted surface cleaning

N-polar aluminum nitride (AlN) is an important building block for next-generation high-power radio frequency electronics. We report successful homoepitaxial growth of N-polar AlN by molecular beam epitaxy (MBE) on large-area, cost-effective N-polar AlN templates. Direct growth without any in situ su...

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Bibliographic Details
Published in:Science advances 2022-09, Vol.8 (36), p.eabo6408-eabo6408
Main Authors: Zhang, Zexuan, Hayashi, Yusuke, Tohei, Tetsuya, Sakai, Akira, Protasenko, Vladimir, Singhal, Jashan, Miyake, Hideto, Xing, Huili Grace, Jena, Debdeep, Cho, YongJin
Format: Article
Language:English
Subjects:
Applied Physics
ENGINEERING
Materials Science
Physical and Materials Sciences
SciAdv r-articles
Science & Technology
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Summary:N-polar aluminum nitride (AlN) is an important building block for next-generation high-power radio frequency electronics. We report successful homoepitaxial growth of N-polar AlN by molecular beam epitaxy (MBE) on large-area, cost-effective N-polar AlN templates. Direct growth without any in situ surface cleaning leads to films with inverted Al polarity. It is found that Al-assisted cleaning before growth enables the epitaxial film to maintain N-polarity. The grown N-polar AlN epilayer with its smooth, pit-free surface duplicates the structural quality of the substrate, as evidenced by a clean and smooth growth interface with no noticeable extended defects generation. Near band-edge photoluminescence peaks are observed at room temperature on samples with MBE-grown layers but not on the bare AlN templates, implying the suppression of nonradiative recombination centers in the epitaxial N-polar AlN. Atomic surface cleaning has enabled successful growth of ultrawide bandgap nitrogen-polar aluminum nitride semiconductors.
ISSN:2375-2548
2375-2548
DOI:10.1126/sciadv.abo6408