• GaN-on-Si;
  • void formation;
  • GaN decomposition;
  • metal-organic vapour phase epitaxy


During the growth of GaN on Si (111), voids were found in GaN layers in between AlN interlayers. Void formation mechanism is the decomposition of GaN in H2. Void formation process is carefully studied. It is clarified that voids are formed during the period between the growth of two neighbouring GaN layers, after the growth of AlN interlayer between them. There are some openings in AlN interlayers and they act as the pass for H2 to react with GaN. NH3 partial pressure, temperature, etching time, and conditions such as thickness of AlN interlayers can be utilized to tune the volume, size and shape of the voids. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)