9632252 Cahill This research project aims for fundamental understanding of ion-induced surface damage using atomic resolution STM and molecular dynamics(MD) computer simulation methods. The approach is to characterize a wide variety of materials and correlate the damage observed using the STM to MD simulations of the ion-surface collisions; the research is also oriented toward critically testing some of the assumptions commonly made in MD simulations. Defect generation in solids is a complex many-body process which cannot be theoretically treated in the binary collision approximation. Collective behaviors such as thermal spikes play a critical role in determining defect structures and are increasingly important for precision ion-beam processing applications such as shallow implant doping of semiconductors. A variety of materials(Ge, Si, Au, Pt, Cu, Ni, GaAs, GaN and amorphous NiZr) will be grown by MBE and examined by STM for ion impacts using Ga, In, and Au in the energy range of 1 keV to 40 keV. MD simulations will be performed for 5-15 keV impacts on Ge, Pt, and amorphous Cu to elucidate the mechanisms of surface damage. %%% The research will contribute basic materials science knowledge at a fundamental level of broad technological relevance to advanced electronic materials processing. Additionally, the knowledge and understanding gained from this research project is expected to contribute in a general way to improving the performance of advanced devices and circuits by providing a fundamental understanding and a basis for designing and processing more advanced materials and devices. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***
