Reemission of implanted xenon by 100-270 keV helium

Reemission of implanted xenon from silicon due to bombardment with 100-270 keV He ⁺ has been investigated at impact angles between 50° and 75° to the surface normal. Doping of the silicon substrates was accomplished by single (1 keV) or double (5 keV +1 keV) implantation of Xe at normal incidence. The depth profiles of Xe and changes thereof were monitored by repeatedly recording backscattering spectra at the same spot of the doped sample. It was found that the areal density of implanted Xe decreases exponentially with increasing He fluence. The cross sections for reemission range from 10 ^-18 to 10 ^-17 cm ² and increase with decreasing He energy, increasing angle of incidence and decreasing distance from the surface. Analysis on the basis of the Rutherford scattering law suggests that the loss of Xe is due to beam induced detrapping followed by outdiffusion.