Si nanoripples: A growth dynamical study

Si(1 0 0) surface was physically eroded using 1 keV Oimage ion beam and the resultant surface was studied by atomic force microscopy (AFM). The data were analyzed within the framework of dynamic scaling theory. Results indicate two growth regimes during the evolution of ripples on the surface. The first growth regime which is an unstable one continues for around 35 min and has an exponential growth exponent. The second growth regime on the other hand sets in after this time and exhibits a growth exponent of 0.38. However, for the entire bombarding period a single coarsening exponent (1/z = 0.44) extracted from the power spectral density peak widths of the acquired AFM images is observed. The ripple amplitudes however show an exponential increase over the time domain studied in agreement with the Bradley–Harper theory. Finally, roughness measurements clearly indicate transition regions of sputter yield variations and the onset of ripple formation.