A scanning tunneling microscope is developed for the invetigation of microtopography and of phase states of silicon sufraces after ion bombardment and laser annealing. Columnar structures are observed after sputtering as well as phase precipitations after hith ion implantation doese. Studies of I–U characteristics allow to determine the local phase state of the surface. Phase transformations from the crystalline (c‐Si) to the amorphous state (α‐Si) of silicon surfaces are induced by low dose implantation. The electron and laser beam methods are used for microlithography, inducing a retransformation from α‐Si to c‐Si. In such a way submicrometer lines and points were formed on the implanted suface and imaged with STM.