A MECHANISM OF ION-BOMBARDMENT INDUCED RIPPLE TOPOGRAPHY

Formation and development of ion bombardment induced morphology on the surfaces of amorphous solids have been investigated by a computer sim ulation code. The code calculates the surface topography depending on the sputtering yield- incident angle function, distribution of sputter ing yield along surface, reflection and shadow effect. It has been sho wn that the main cause of the formation of the ripple morphology on th e surface is the distribution of the sputtering yield along the surfac e depending on the incident point and incident angle (''downstream'' e ffect). The wavelength of the ripple depends on the range of the sputt ering plot on the surface, and is 10-13 times the distance between the impact point and the point of the maximum sputtering yield.