Damage in crystalline silicon by swift heavy ion irradiation

We have studied damage of crystalline Si surfaces induced by electronic energy loss of swift heavy ions with an electronic stopping power of up to Se = 12 keV/nm. Scanning tunneling microscope images of the surface after irradiation under perpendicular as well as glancing angles of incidence showed no surface damage. We have performed theoretical calculations for the damage threshold within the two temperature model, resulting in Seth=8 keV/nm as the minimum stopping power to create a molten zone. We investigate the respective influence of the electron–phonon coupling, of the criterion at which the damage occurs and a possible effect of ballistic electrons. We show that the latter has the strongest effect on the calculated damage threshold.