NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
Issue Date:
1999
Abstract(summary):
Diffuse X-ray scattering (DXS) at glancing incidence is a potentially powerful means for elucidating damage structures in irradiated solids. Fundamental to the analysis of diffuse X-ray scattering data is a knowledge of the atomic displacement field around defects, which for implantation damage in crystals like Si has been difficult to obtain using analytical solutions of elastic continuum theory. We present a method for predicting the diffuse scattering pattern by calculating the displacement field around a defect using fully atomistic simulations and performing discrete sums for the scattering intensity. We apply the method to analyze experimental DXS results of defects produced by 4.5 keV He and 20 keV Ga irradiations of Si at temperatures of 100-300 K. The results show that the self-interstitial in ion-irradiated Si becomes mobile around 150 K, and that amorphization of silicon by light and medium-heavy projectiles occurs homogeneously through the buildup of interstitial clusters, and not within single cascade events. (C) 1999 Elsevier Science B.V. All rights reserved.