TY - JOUR
T1 - Crystal structure and composition of BAlN thin films
T2 - Effect of boron concentration in the gas flow
AU - Wang, Shuo
AU - Li, Xiaohang
AU - Fischer, Alec M.
AU - Detchprohm, Theeradetch
AU - Dupuis, Russell D.
AU - Ponce, Fernando
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 °C, 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 from x = 0.06 to 0.16, closely following the gas-flow ratios. Transmission electron microscopy indicates the sole presence of a 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 have studied, which is significantly higher than previously thought.
AB - We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 °C, 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 from x = 0.06 to 0.16, closely following the gas-flow ratios. Transmission electron microscopy indicates the sole presence of a 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 have studied, which is significantly higher than previously thought.
KW - A1. Characterization
KW - A1. Crystal structure
KW - A3. Metalorganic chemical vapor deposition
KW - B1. Nitrides
KW - B2. Semiconducting III–V materials
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U2 - 10.1016/j.jcrysgro.2017.07.013
DO - 10.1016/j.jcrysgro.2017.07.013
M3 - Article
AN - SCOPUS:85026251591
SN - 0022-0248
VL - 475
SP - 334
EP - 340
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
ER -