STM observation of ‘craters’ on graphite surface induced by single ion implantation

In the course of developing single ion implantation (SII) technology for control of doping in semiconductor fine structures and modification of surfaces/interfaces, both in an atomic scale, defect generation by single ions in the surface region of graphite has been investigated with scanning tunneling microscopy (STM). Argon ions with acceleration energy of 30 to 60 keV have been implanted into highly oriented graphite crystal. Craters have been formed at the ion incident sites. The feature of craters shows swelling from the undamaged surroundings. The volume of the swelling fluctuates among the craters, which reflects the fluctuation in the number of ion-induced defects near the surface. A good correlation between the amount of the surface defects and the projected range of each implanted ion has been confirmed by simulation of cascading. Consequently it has been found that the swelling volume of individual craters characterized by STM can be a good measure of the statistical distribution of each implanted ion and ion induced defect distribution.