Crystal structure and composition of BAlN thin films: Effect of boron concentration in the gas flow

Shuo Wang, Xiaohang Li, Alec M. Fischer, Theeradetch Detchprohm, Russell D. Dupuis, Fernando A. Ponce

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 oC, with B/(B+Al) gas-flow ratios ranging from 0.06 to 0.18. The boron content obtained from X-ray diffraction (XRD) patterns ranges from x = 0.02 to 0.09. On the other hand, boron content deduced from the aluminum signal in the Rutherford backscattering spectra (RBS) ranges x = 0.06 to 0.16, closely following gas-flow ratios. Transmission electron microscopy indicates the sole presence of wurtzite crystal structure in the BAlN films, and a tendency towards columnar growth for B/(B+Al) gas-flow ratios below 0.12. For higher ratios, the BAlN films exhibit a tendency towards twin formation and finer microstructure. Electron energy loss spectroscopy has been used to profile spatial variations in the composition of the films.The RBS data suggest that the incorporation of B is highly efficient for our growth method, while the XRD data indicate that the epitaxial growth may be limited by a solubility limit in the crystal phase at about 9%, for the range of B/(B+Al) gas-flow ratios that we used, which is significantly higher than previously thought.
Original languageEnglish (US)
Pages (from-to)334-340
Number of pages7
JournalJournal of Crystal Growth
Volume475
DOIs
StatePublished - Jul 20 2017

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