Growth of AlN crystals on AlN/SiC seeds by AlN powder sublimation in nitrogen atmosphere
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Growth of AlN crystals on AlN/SiC seeds by AlN powder sublimation in nitrogen atmosphere V. Noveski, R. Schlesser, S. Mahajan, S. Beaudoin and Z. Sitar MRS Internet Journal of Nitride Semiconductor Research / Volume 9 / January 2004 DOI: 10.1557/S1092578300000375, Published online: 13 June 2014
Link to this article: http://journals.cambridge.org/abstract_S1092578300000375 How to cite this article: V. Noveski, R. Schlesser, S. Mahajan, S. Beaudoin and Z. Sitar (2004). Growth of AlN crystals on AlN/SiC seeds by AlN powder sublimation in nitrogen atmosphere . MRS Internet Journal of Nitride Semiconductor Research, 9, pp e2 doi:10.1557/S1092578300000375 Request Permissions : Click here
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Internet Journal Nitride Semiconductor Research
Growth of AlN crystals on AlN/SiC seeds by AlN powder sublimation in nitrogen atmosphere V. Noveski12, R. Schlesser1, S. Mahajan2, S. Beaudoin3 and Z. Sitar1 1Department
of Materials Science and Engineering, North Carolina State University, of Chemical and Materials Engineering, Arizona State University, 3School of Chemical Engineering, Purdue University, 2Department
(Received Tuesday, November 18, 2003; accepted Monday, February 9, 2004)
AlN single crystals were grown on AlN/SiC seeds by sublimation of AlN powder in TaC crucibles in a nitrogen atmosphere. The seeds were produced by metallorganic chemical vapor deposition (MOCVD) of AlN on SiC crystals. The influence of growth temperature, growth time and source-toseed distance on the crystallinity and the crystal growth rate were investigated. Crystals were grown in an RF heated sublimation reactor at growth temperatures ranging from 1800-2000°C, at a pressure of 600 Torr, nitrogen flow-rate of 100 sccm and source-to-seed distances of 10 and 35 mm. At 1870°C and a source-to-seed distance of 35 mm, isolated crystals were observed with few instances of coalescence. At 1930°C, a source-to-seed distance of 10 mm and longer growth times (~30 hrs), crystal coalescence was achieved. Above 1930°C, the decomposition of SiC was evidently affecting the growth morphology and resulted in growth of polycrystalline AlN. After an initial nucleation period, the observed growth rates (10-30 µm/hr) were in close agreement with predictions of a growth model that assumed gas-phase diffusion controlled growth. Optical and electron microscope observations revealed step-flow growth, while X-ray diffraction results showed the single crystal nature of the grown material. Single crystalline AlN was grown over surface areas of 200-300 mm2 and was transparent and essentially colorless.
1 Introduction AlN has been identified as a promising material for a wide range of electronic, optoelectronic and acoustic applications, due to its chemical, mechanical and thermal stability, wide direct bandgap (6.2 eV),
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