Dislocation Bundles in GaAs Substrates: Assessed by X-Ray and Makyoh Topography, X-Ray Diffraction, Scanning Infrared Polariscopy, Light Interferometry and Nomarski Microscopy
Different types of dislocation bundles are identified in GaAs Substrates of III-V heterostructures. Comparisons of X-ray transmission topograms with scanning infrared polariscopy images show a one to one correlation of stripes of reduced residual shear stain and dislocation bundles of the majority type. Makyoh topography, visible light interferometry and standard Nomarski microscopy, on the other hand, show a slip-line distribution that is in correspondence to the distribution of dislocation bundles of a minority type. Utilising several complementary technique, the number and density of heat treatment induced dislocations in two-inch diameter substrates are estimated.