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Keywords:

  • MOVPE;
  • semi-polar GaN;
  • silicon substrate;
  • basal plane stacking faults (BSFs)

Abstract

We report on metal organic vapor phase epitaxy of semi-polar growth of nearly (1equation image06) oriented GaN films on Si(112) and (1equation image05) and (1equation image04) GaN on Si(113). We analyze the GaN crystallites by field emission-scanning electron microscopy (FE-SEM), scanning transmission electron microscopy (STEM), photoluminescence (PL), and cathodoluminescence (CL). A correlation between optical properties and microstructure is presented. Our studies reveal a significant reduction of basal plane stacking faults (BSFs) in semi-polar GaN grown on planar Si(112) by applying a low temperature (LT) AlN interlayer. We find that the insertion of the LT-AlN interlayer can eliminate the stacking faults in the upper GaN layer, when the LT-AlN interlayer is inserted on a smooth GaN buffer. The LT-AlN interlayer results in lattice relaxation due to misfit dislocation formation at the GaN/LT–AlN interface. In comparison, GaN grown on Si(113) with same growth conditions and a rough GaN surface does not show any BSF reduction while it is reduced for a smooth GaN layer (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)