Properties of GaN Epitaxial Layers Grown on 6H-SiC(0001) by Plasma-Assisted Molecular Beam Epitaxy
Authors: Lee, C.D.; Ramachandran, V.; Sagar, A.; Feenstra, R.M.; Greve, D.W.; Sarney, W.L.; Salamanca-Riba, L.; Look, D.C.; Bai, Song; Choyke, W.J.; Devaty, R.P.
Source: Journal of Electronic Materials, Volume 30, Number 3, 1 March 2001 , pp. 162-169(8)
Abstract:The structural, electrical, and optical properties of GaN grown on 6H-SiC(0001) substrates by molecular beam epitaxy are studied. Suitable substrate preparation and growth conditions are found to greatly improve the structural quality of the films. Threading dislocation densities of about 3 × 109 cm-2 for edge dislocations and <1 × 106 cm-2 for screw dislocations are achieved in GaN films of 0.8 m thickness. Mechanisms of dislocation generation and annihilation are discussed. Increasing the Ga to N flux ratio used during growth is found to improve the surface morphology. An unintentional electron concentration in the films of about 5 × 1017 cm-3 is observed, and is attributed to excess Si in the films due to a Si-cleaning step used in the substrate preparation. Results from optical characterization are correlated with the structural and electronic studies.
Document Type: Research Article
Publication date: 2001-03-01