Journal of Crystal Growth, Vol.305, No.2, 311-316, 2007
Seeded growth of GaN by the basic ammonothermal method
Two preliminary experiments are reviewed and seeded growth of GaN is updated in this paper. In a mineralizer Study, it was shown that basic mineralizers promoted synthesis of wurtzite GaN. Through a dissolution study of polycrystalline GaN in basic supercritical ammonia, it was confirmed that GaN has retrograde solubility. A GaN film as thick as 45 mu m was obtained in seeded growth from metallic Ga nutrient. Uniform growth of GaN over a 3 x 4cm (2) oval-shaped seed crystal was also demonstrated. Seeded growth of GaN from polycrystalline GaN nutrient was attempted to avoid growth saturation problem in Ga nutrient. Extended growth lip to I I days was attained with increased mineralizer concentration. The cross-sectional TEM observation showed high density of voids and defects at the 2roNvth interface, although most of them did not propagate to the top surface. The estimated threading dislocation density was at the order of low-10(9) Cm-2 and no evidence of basal plane stacking fault was observed. (c) 2007 Elsevier B.V. All rights reserved.