Type
ArticleAuthors
Sun, Haiding
Wu, Feng
Park, Young Jae
Al tahtamouni, T. M.

Li, Kuang-Hui
Alfaraj, Nasir

Detchprohm, Theeradetch
Dupuis, Russell D.

Li, Xiaohang

KAUST Department
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) DivisionElectrical Engineering Program
Date
2017-05-12Online Publication Date
2017-05-12Print Publication Date
2017-05-08Permanent link to this record
http://hdl.handle.net/10754/623481
Metadata
Show full item recordAbstract
The trimethylaluminum (TMAl) preflow process has been widely applied on sapphire substrates prior to growing Al-polar AlN films by metalorganic chemical vapor deposition. However, it has been unclear how the TMAl preflow process really works. In this letter, we reported on carbon's significance in the polarity and growth mode of AlN films due to the TMAl preflow. Without the preflow, no trace of carbon was found at the AlN/sapphire interface and the films possessed mixed Al- and N-polarity. With the 5 s preflow, carbon started to precipitate due to the decomposition of TMAl, forming scattered carbon-rich clusters which were graphitic carbon. It was discovered that the carbon attracted surrounding oxygen impurity atoms and consequently suppressed the formation of AlxOyNz and thus N-polarity. With the 40 s preflow, the significant presence of carbon clusters at the AlN/sapphire interface was observed. While still attracting oxygen and preventing the N-polarity, the carbon clusters served as randomly distributed masks to further induce a 3D growth mode for the AlN growth. The corresponding epitaxial growth mode change is discussed.Citation
Influence of TMAl preflow on AlN epitaxy on sapphire 2017, 110 (19):192106 Applied Physics LettersSponsors
The KAUST authors would like to acknowledge the support of GCC Research Program REP/1/3189-01-01, Baseline BAS/1/1664-01-01, and Equipment BAS/1/1664-01-07. The work at QU was supported by GCC Research Program GCC-2017–007. The work at Georgia Institute of Technology was supported in part by DARPA under Grant No. W911NF-15-1-0026 and NSF under Grant No. DMR-1410874. R.D.D. acknowledges the additional support of the Steve W. Chaddick Endowed Chair in Electro-Optics and Georgia Research Alliance.Publisher
AIP PublishingJournal
Applied Physics LettersAdditional Links
http://aip.scitation.org/doi/10.1063/1.4983388ae974a485f413a2113503eed53cd6c53
10.1063/1.4983388