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The benefits of dry oxidation of n ‐GaN for the fabrication of metal‐oxide‐semiconductor structures are reported. GaN thin films grown on sapphire by MOCVD were thermally oxidized for 30, 45 and 60 minutes in a pure oxygen atmosphere at 850 °C to produce thin, smooth GaOx layers. The GaN sample oxidized for 30 minutes had the best properties. Its surface roughness (0.595 nm) as measured by atomic force microscopy (AFM) was the lowest. Capacitance‐voltage measurements showed it had the best saturation in accumulation region and the sharpest transition from accumulation to depletion regions. Under gate voltage sweep, capacitance‐voltage hysteresis was completely absent. The interface trap density was minimum (Dit = 2.75×1010 cm–2eV–1) for sample oxidized for 30 mins. These results demonstrate a high quality GaOx layer is beneficial for GaN MOSFETs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Aluminum nitride (AlN) was grown on c‐plane sapphire substrates by hydride vapor phase epitaxy (HVPE). The experiments utilized a two zone inductively heated hot‐wall reactor capable of temperatures exceeding 1500 °C. The precursors of aluminum monochloride (AlCl) and aluminum trichloride (AlCl3) were used, and it was determined that AlCl3 was more thermodynamically conducive to single crystalline AlN growth at 1450 °C. AlN templates were optimized at a thickness of 1 µm without cracking. The double axis X‐ray diffraction (XRD) rocking curves full width half maximums (FWHMs) were reproducibly demonstrated with an average of 130 arcsec for the (002) and 516 arcsec for the (102). The AlN was transparent in the UV spectrum with a band gap cut off of 200 nm. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The crystallographic properties of bulk icosahedral boron arsenide (B12As2) crystals grown by precipitation from molten nickel solutions were characterized. Large crystals (5-8 mm) were produced by dissolving the boron in nickel at 1150°C for 48-72 hours, reacting with arsenic vapor, and slowly cooling to room temperature. The crystals varied in color from black and opaque to clear and transparent. Raman spectroscopy, x-ray topography (XRT), and defect selective etching revealed that the B12As2 single crystals were high quality with low dislocation densities. Furthermore, XRT results suggest that the major face of the plate-like crystals was (111) type, while (100), (010) and (001) type facets were also observed optically. The predominant defect in these crystals was edge character growth dislocations with a <001> Burgers vector, and <-110> line direction. In short, XRT characterization shows that solution growth is a viable method for producing good quality B12As2 crystals.