The effect of bismuth ion implantation (dose range 10 15–10 18 cm −2) on the surface morphology of monocrystalline silicon was investigated by Atomic Force Microscopy (AFM) and Cross-Sectional Transmission Electron Microscopy (XTEM) and the data obtained compared. The low levels of roughness observed at dose interval 10 15–6×10 15 cm −2 could be related to an amorphous layer created at the target surface. Roughness increased at a dose of 8×10 15 cm −2, where drastic changes in the morphology of the amorphous layer began, i.e. with nonepitaxial recrystallization of Si and simultaneous agglomeration of Bi in nanocrystals. The maximum surface roughness at a dose 1×10 18 cm −2 was related to the specific erosion of the surface in the form of hillocks connected to the extremely large value of the sputtering yield of Bi (61.8 at. i. −1 ) in comparison with the sputtering yield of Si (3 at. i. −1).