Wavelike Periodic Structures on the Silicon Surface Initiated by Irradiation with a Focused Gallium Ion Beam

We investigate the processes of microrelief formation on a Si(100) surface under irradiation with a Ga⁺-ion beam with an energy of 30 keV and a fluence of D = 1.25 × 10¹⁸–2 × 10¹⁹ cm^–2 at incident angles of θ = 30°–85°. Within the angular range of θ = 40°–70°, a faceted wavy relief forms on the Si surface, while at θ = 30°, a sinusoidal relief develops. An experimental dependence of the periodic structure wavelength as a function of irradiation time λ(t) ~ t ⁿ, where n = 0.33–0.35, is obtained. The average values of relief propagation velocities and their direction relative to the incident ion direction are determined for θ = 30° and 40°, amounting to –5.3 ± 0.6 and –6.3 ± 0.6 nm s^–1, respectively. The results are discussed in detail within the framework of existing models of wavelike surface relief formation under ion bombardment.