Topographical structure of MBE grown cubic inxGa1-x films studied with a MeV ion microprobe and by AFM

Abstract

Cubic InxGa1-xN films (x = 0.02), grown on (001) GaAs substrates by plasma-assisted MBE, have been studied by 2 MeV He+ channeling, with both RBS and PIXE detection, using a scanning nuclear microprobe to achieve lateral resolution of a few microns. A laterally constant surface segregation of indium with decay lengths of the order of 50 nm was observed by RBS in all samples. Lateral indium L X-ray yield fluctuations on a scale of 10 μm were observed by micro-PIXE, but not by micro-RBS, in one sample. They could be attributed to thickness variations of the epitaxial cubic InxGa1-xN layer arising from Ga droplet formation during epitaxial growth, taking into account the different analysis dept..