Growth of Ga- and N- polar gallium nitride layers by metalorganic vapor phase epitaxy on sapphire wafers

Collazo, Ramón; Mita, Seiji; Aleksov, A.; Schlesser, R.; Sitar, Zlatko

doi:10.1016/j.jcrysgro.2005.10.080

Cited by 74 publications

(69 citation statements)

References 6 publications

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“…However, our experiments show that under the same conditions N-face and Ga-face c-plane GaN have similar growth rates, which was also verified by others. 21 Therefore, we speculate that this phenomenon may be related to differences in chemical stability of Ga-and N-faces since the latter has been shown to be less resistive to wet chemical etching. 22 During the growth of a-GaN, relatively lower amount of ammonia and higher growth temperature in hydrogen atmosphere may make N-face even less stable than the Ga-face, thereby inducing a smaller growth rate for the N-face GaN.…”

Section: Resultsmentioning

confidence: 95%

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Özgür

et al. 2006

Applied Physics Letters

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In the epitaxial lateral overgrowth (ELO) of (1120) a-plane GaN, the uneven growth rates of two opposing wings, Ga-and N-wings, makes the coalescence of two neighboring wings more difficult than that in c-plane GaN. We report a two-stage growth method to get uniformly coalesced epitaxial lateral overgrown a-plane GaN using metalorganic chemical vapor deposition (MOCVD) by employing relatively lower growth temperature in the first step followed by enhanced lateral growth in the second. Using this method, the height differences between Ga-polar and N-polar wings at the coalescence front could be reduced, thereby making the coalescence of two wings much easier. Transmission electron microscopy (TEM) showed that the threading dislocation density in the wing areas was 1.0×10 8 cm -2 , more than two orders of magnitude lower than that in the window areas (4.2×10 10 cm -2 ). However, high density of basal stacking faults of 1.2×10 4 cm -1 was still observed in the wing areas as compared to c-plane GaN. Atomic force microscopy and photoluminescence

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Section: Resultsmentioning

confidence: 95%

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Özgür

et al. 2006

Applied Physics Letters

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“…To explore this hypothesis, CaO thin films were grown by oxide MBE onto [0001] oriented Ga-face c + -polar films that exhibit a single and uniform polar orientation 16 . Ca was evaporated from a thermal source while the oxidant was supplied as an ambient of either molecular oxygen or water vapour.…”

Section: Film Depositionmentioning

confidence: 99%

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

et al. 2011

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Property coupling at interfaces between active materials is a rich source of functionality, if defect densities are low, interfaces are smooth and the microstructure is featureless. Conventional synthesis techniques generally fail to achieve this when materials have highly dissimilar structure, symmetry and bond type-precisely when the potential for property engineering is most pronounced. Here we present a general synthesis methodology, involving systematic control of the chemical boundary conditions in situ, by which the crystal habit, and thus growth mode, can be actively engineered. In so doing, we establish the capability for layer-by-layer deposition in systems that otherwise default to island formation and grainy morphology. This technique is demonstrated via atomically smooth {111} calcium oxide films on (0001) gallium nitride. The operative surfactant-based mechanism is verified by temperature-dependent predictions from ab initio thermodynamic calculations. Calcium oxide films with smooth morphology exhibit a three order of magnitude enhancement of insulation resistance.

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“…This effect became more pronounced as the Sc flux was increased to 4 nA, where the Sc contents measured by XPS are 0.31, 0.27 and 0.21 respectively. This is likely due to the differences in surface polarity expected to occur between III-nitride films grown by MBE (normally N-polar) and MOVPE (normally Ga-polar) [49,50], as well as differences in the film strain which are well known to affect the relative incorporation of alloy constituents having different ionic radii [51,52] and which may also affect the relative surface accumulation.…”

Section: Methodsmentioning

confidence: 99%

Composition measurement of epitaxial Sc_xGa_1−xN films

Tsui

Goff

Barradas

et al. 2016

Semicond. Sci. Technol.

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Four different methods for measuring the compositions of epitaxial Sc x Ga 1-x N films were assessed and compared to determine which was the most reliable and accurate. The compositions of epitaxial Sc x Ga 1-x N films with 0 ≤ x ≤ 0.26 were measured directly using Rutherford backscattering (RBS) and X-ray photoelectron spectroscopy (XPS), and indirectly using c lattice parameter measurements from X-ray diffraction and c/a ratio measurements from electron diffraction patterns. RBS measurements were taken as a standard reference. XPS was found to underestimate the Sc content, whereas c lattice parameter and c/a ratio were not reliable for composition determination due to the unknown degree of strain relaxation in the film. However, the Sc flux used during growth was found to relate linearly with x and could be used to estimate the Sc content.

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Growth of Ga- and N- polar gallium nitride layers by metalorganic vapor phase epitaxy on sapphire wafers

Cited by 74 publications

References 6 publications

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

Composition measurement of epitaxial Sc_xGa_1−xN films

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Growth of Ga- and N- polar gallium nitride layers by metalorganic vapor phase epitaxy on sapphire wafers

Cited by 74 publications

References 6 publications

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Defect reduction in (112¯) a-plane GaN by two-stage epitaxial lateral overgrowth

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

Composition measurement of epitaxial ScxGa1−xN films

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Product

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Composition measurement of epitaxial Sc_xGa_1−xN films