Temperature Dependence of the Nanostructure Morphology during Sputtering of Silicon by Nitrogen Ions

Temperature dependences of the period of wavelike nanostructures λ(T) in the N₂⁺ –Si system were obtained in the range from room temperature (TR) to 973 K. For ion energies E = 8 and 5 keV, constant λ values were observed in the range TR—700 K, while a decrease in λ was observed in the range 700–973 K. For E = 1.6 keV, the nanostructure period remained constant at λ ≈ 30 nm at temperatures from TR to 973 K. The λ(T) dependences are discussed from the standpoint of an approach that considers the formation of wavelike structures based on stresses caused by amorphization of the altered layer and their relaxation due to ion-induced viscous flow. Under conditions of cyclic exposure to a nitrogen ion flux at T = 973 K, a nanostructure is formed in the form of an array of silicon nitride nanodots with a period of about 100 nm.