Glancing incidence diffuse X-ray scattering studies of implantation damagein Si

Diffuse X-ray scattering (DXS) at glancing incidence is a potentially power ful means for elucidating damage structures in irradiated solids. Fundament al to the analysis of diffuse X-ray scattering data is a knowledge of the a tomic displacement field around defects, which for implantation damage in c rystals like Si has been difficult to obtain using analytical solutions of elastic continuum theory. We present a method for predicting the diffuse sc attering pattern by calculating the displacement field around a defect usin g fully atomistic simulations and performing discrete sums for the scatteri ng intensity. We apply the method to analyze experimental DXS results of de fects produced by 4.5 keV He and 20 keV Ga irradiations of Si at temperatur es of 100-300 K. The results show that the self-interstitial in ion-irradia ted Si becomes mobile around 150 K, and that amorphization of silicon by li ght and medium-heavy projectiles occurs homogeneously through the buildup o f interstitial clusters, and not within single cascade events. (C) 1999 Els evier Science B.V. All rights reserved.