Conditions for seeded growth of GaN crystals by the Na flux method

Conditions for seeded growth of GaN crystals by the Na flux method were investigated. Seeded growth in the Na flux could be achieved under temperature-N-2 pressure conditions between the condition of GaN formation without seeding and the condition of GaN decomposition. GaN single crystals with a maximum area of 3.0 x 1.5 mm(2) and thickness of 1.0 mm were gown from seeds at 850 degreesC and 2 MPa of N-2 for 200 h. The crystal growth occurred selectively on the (0001) Ga-polar surface of the platelet seed crystals. The growth rate in the c direction was higher than those of other directions and increased with growth temperature and N-2 pressure. The maximum growth rate in the c direction was about 4 mum/h at 850 degreesC and 2 MPa of N-2. (C) 2002 Elsevier Science B.V All rights reserved.