MASK EDGE EFFECTS IN HIGH-ENERGY IMPLANTS - DOPANT AND DEFECT DISTRIBUTIONS

MeV boron implants were performed on silicon substrates patterned with an oxide mask. Secondary defects, generated after annealing under the mask edge, were studied by cross sectional transmission electron microscopy. The relative doped regions formed by these implants were investigated by one- and two-dimensional spreading resistance profiling and compared with analytical and Monte Carlo calculations provided by SUPREM IV and STORM, the most used 2D process simulators in microelectronic technology. The density of defects and the two-dimensional profiles of B were related to the slope of the oxide mask edge. The increase of lateral spread is simply due to the ion penetration through the edge of the oxide mask. The formation of defects is instead explained in terms of the amount of displaced Si atoms under the oxide mask.