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Hydride Vapor Phase Epitaxy (hydride + vapor_phase_epitaxy)
Selected AbstractsBulk growth of gallium nitride: challenges and difficultiesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2007M. Bockowski Abstract The present status of the GaN bulk growth by High Pressure Solution (HPS) method and combination of HPS and Hydride Vapor Phase Epitaxy (HVPE) methods is reviewed. Up to now the spontaneous high pressure solution growth of GaN results in crystals having habit of hexagonal platelets of surface area of 3 cm2 or needles with length up to 1 cm. Recently, the platelets and needles have been used as seeds for the HVPE growth. On the other hand, the LPE technique under pressure with pressure-grown GaN (hp-GaN), GaN/sapphire template, patterned GaN/sapphire template and free standing HVPE GaN as seeds has been examined and developed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Growth of GaN on a -plane sapphire: in-plane epitaxial relationships and lattice parametersPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003T. Paskova Abstract We have studied GaN films grown on a -plane sapphire substrates by both hydride vapor phase epitaxy (HVPE) and metalorganic vapor phase epitaxy (MOVPE). The in-plane orientation relationships between the epitaxial films and the substrate are determined to be [11,20]GaN , [0001]sapphire and [1,100]GaN , [1,100]sapphire in the HVPE growth, while [1,100]GaN , [0001]sapphire and [11,20]GaN , [1,100]sapphire are found in the MOVPE growth. The different orientation preferences are attributed to the atom termination of the sapphire surface determined by the substrate treatment used in the different growth methods. The effect of the lattice matches on the in-plane lattice parameters and strain anisotropy in the two cases is studied. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Investigation of polarity dependent InN{0001} decomposition in N2 and H2 ambientPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009R. Togashi Abstract The polarity dependence of decomposition of the (0001) In- and (000) N-polarity InN layers grown by hydride vapor phase epitaxy (HVPE) on freestanding GaN substrates was investigated. In flowing N2, In- and N-polarity InN layers start to decompose over 550 and 610 °C, respectively. Therefore, the N-polarity InN layer is more stable than the In-polarity InN layer. On the other hand, in flowing H2, InN layers of both polarities start to react with H2 at a low temperature of 350 °C leaving In droplets on the surfaces. Further more, the decomposition rate of the N-polarity InN layer is larger than that of the In-polarity InN layer below approximately 450 °C, while the decomposition rate of the In-polarity InN layer is larger than that of the N-polarity InN above 450 °C. An Arrhenius plot of the decomposition rates revealed that the activation energies, EA, for the decomposition reactions of In- and N- polarity InN layers are 168 and 107 kJ/mol, respectively, which are much smaller than that for GaN and AlN decomposition. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of initial conditions and growth temperature on the properties of nonpolar a -plane AlN grown by LP-HVPEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009Jie-Jun Wu Abstract AlN was grown on r - and c -plane sapphire substrates by low-pressure hydride vapor phase epitaxy (LP-HVPE). Nitridation and buffer methods were used and compared. Results show that the buffer method is appropriate for the growth of a-plane AlN. In-plane stresses were measured and found to be different in the two in-plane directions parallel and perpendicular to the AlN c -axis. In-plane stress anisotropy is reduced at high temperature leading to a smoother surface, partly owing to a decreased difference in the growth rates between two in-plane directions. However, too high a temperature decreases the crystal quality of a-plane AlN. Thus, there exists an optimal temperature range for the growth of a-plane AlN, in which improved crystal and surface qualities can both be obtained. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrical and optical properties of thick highly doped p-type GaN layers grown by HVPEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008A. Usikov Abstract In this paper we report 3-7 ,m thick p-GaN growth by hydride vapor phase epitaxy (HVPE) on sapphire substrates. Mg impurity was used for doping. As-grown GaN layers had p-type conductivity with concentration NA -ND up to 3×1019 cm,3. Mg atom concentration was varied from 1017 to 1020 cm,3. Hydrogen concentration was about 10 times less than that for Mg, which may explain effective p-type doping for as-grown GaN layers. Micro-cathodoluminescence revealed a columnar-like structure of the GaN layers with a non-uniform distribution of material regions having dominant 362 nm or 430 nm luminescence. Use of these thick p-GaN layers to grow InGaN-based blue and green LEDs by the HVPE is demonstrated. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High temperature growth of AlN film by LP-HVPEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007K. Tsujisawa Abstract AlN films were grown on AlN/sapphire templates at 1400,1500 °C using low-pressure hydride vapor phase epitaxy (LP-HVPE). Compared to the step-flow growth of AlN film at 1200 °C with growth rate of 2.1 ,m/h, AlN films with atomic steps were obtained at 1400,1500 °C even with high growth rate. For the AlN film grown at 1450 °C with growth rate of 14.3 ,m/h, the RMS value is 0.75 nm and the FWHM values of (0002) and (10-12) X-ray rocking curve (XRC) are 351 and 781 arcsec, respectively. Since the FWHM value of (10-12) XRC for the AlN/sapphire template is 1492 arcsec, the crystal quality of HVPE-grown AlN is greatly improved compared with the AlN/sapphire template, which is also confirmed by TEM observation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fabrication of thick AlN film by low pressure hydride vapor phase epitaxyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006Yu-Huai Liu Abstract Thick AlN crystals were grown by conventional hydride vapor phase epitaxy (HVPE) on AlN/sapphire templates under low pressure (,15 Torr) at high temperature (1100 °C,1200 °C). Colorless, mirror-like AlN films were obtained at the growth rates of up to 20.6 ,m/h. The best root mean square (RMS) value of atomic force microscope (AFM) observations for the AlN surface was 0.19 nm in a surface of 5×5 ,m2. The typical values of full width half maximum (FWHM) of X-ray rocking curves for (0002) and (102) diffraction of AlN films were 173,314 arcsec and 1574,1905 arcsec, respectively. We also investigated the influences of carrier gas, growth temperature and growth rate on the crystal quality. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Defect density dependence of luminescence efficiency and lifetimes in AlGaN active regions exhibiting enhanced emission from nanoscale compositional inhomogeneitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006G. A. Garrett Abstract AlGaN epilayers grown by plasma-assisted molecular beam epitaxy and exhibiting high internal quantum efficiency (up to 30%) are incorporated into double-heterostructure devices grown on base layers of varying defect density. Growth of these AlGaN active layers, having increased emission from localization of carriers in regions of nanoscale compositional inhomogeneities, is found to benefit from base layers of reduced defect density, including thick AlGaN templates grown by hydride vapor phase epitaxy. Nonlinear radiative processes are observed at high optical excitation for layers grown on lower defect base layers. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||