Diffusion of In atoms was observed in InGaN ultra-thin films (3nm thickness), which were prepared by radio-frequency induced N plasma source molecular beam epitaxy and subsequent thermal annealing, using high-resolution Rutherford back-scattering spectrometry. To suppress decomposition of In atoms, cap-GaN layer was grown onto InGaN film. In-related signal clearly appeared in the high-resolution Rutherford back-scattering spectra after post-growth thermal annealing (875C, 600s). The thickness of InGaN layer with post-growth thermal annealing increased comparing with that before annealing; On the contrary, the thickness of the cap-GaN layer decreased. This result indicated that diffusion of In atoms occurred at GaN/InGaN interface. The diffusion coefficient was estimated to be approximately 3.8 x 10-18cm2/s.

Diffusion of In Atoms in InGaN Ultra-Thin Films During Post-Growth Thermal Annealing by High-Resolution Rutherford Back-Scattering Spectrometry. H.Sakuta, Y.Kawano, Y.Yamanaka, S.Kurai, T.Taguchi: Physica Status Solidi C, 2005, 2[7], 2407-10