Epitaxial lateral overgrowth of AlN layers on patterned sapphire substrates

Epitaxial lateral overgrowth (ELO) of low‐dislocation‐density AlN layers on trench‐patterned sapphire substrates is demonstrated for the first time. Sapphire (0001) substrates with trench patterns formed along two different directions, 〈1010 10 0〉 and 〈1111 20 0〉, were used. We can obtain fully coalesced AlN only on the sapphire substrate having 〈1111 20 0〉 trenches. The dislocation density of ELO‐AlN is as low as 6.7 × 108 cm–2. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)