Formation of a periodic structure on the surface of InP crystal during irradiation with bismuth ions

This work is devoted to the study of the formation of periodic relief on the InP surface during ion sputtering by bismuth ions with an energy of 30 keV and an angle of incidence of 45° respect to normal incidence. We compared the reliefs formed by sputtering with atomic and cluster bismuth ions, as well as the relief appearing on the surface of the sample irradiated at elevated temperature (290 °C). Three different types of reliefs were found: surface waves with nanodots on the surface “waves”, nanodots with uniform distribution and relief in the form of columnar micro crystallites during sputtering of a heated target. With increasing irradiation dose, insignificant changes in characteristic surface dimensions were observed for all three reliefs. Based on the nonlinear character of surface sputtering (“thermal spot” sputtering mode), we described the formation of relief in the form of nano-dots and in the form of micro crystallites as a result of local melting areas formation and subsequent solidification (crystallization) on the target surface. Regarding wave relief, in our opinion, an adequate physical description is given by a model based on the stress driven dynamics of ion irradiated surface.