Growth of crack-free hexagonal GaN films on Si(100)

Hexagonal GaN films have been grown on Si(100) substrates by employing a sputtered AlN buffer layer followed by another high-temperature metalorganic chemical vapor deposition (MOCVD) grown AlN buffer layer. The highly oriented structure of sputtered AlN provides a hexagonal template for subsequent AlN and GaN growth. The GaN films are evaluated by transmission electron microscopy, selected area electron diffraction, x-ray diffraction, and photoluminescence and exhibit a purely hexagonal columnar structure. The orientation of the GaN columns depends on the thickness of both the sputtered AlN buffer layer and the MOCVD grown AlN buffer layer. The surface of GaN films is shiny and crack free up to a thickness of 2 mum studied in this work. (C) 2001 American Institute of Physics.