Influence of the narrow {111} planes on axial and planar ion channeling

Abstract

We report channeling patterns where clearly resolved effects of the narrow {111} planes are observed in axial and planar alignments for 2Â MeV protons passing through a 55Â nm [001] silicon membrane. At certain axes, such as â?̈213â?© and â?̈314â?©, the offset in atomic rows forming the narrow {111} planes results in shielding from the large potential at the wide {111} planes, producing a region of shallow, asymmetric potential from which axial channeling patterns have no plane of symmetry. At small tilts from such axes, different behavior is observed from the wide and narrow {111} planes. At planar alignment, distinctive channeling effects due to the narrow planes are observed. As a consequence of the shallow potential well at the narrow planes, incident protons suffer dechanneled trajectories which are excluded from channeling within the wide planes, resulting in an anomalously large scattered beam at {111} alignment. © 2012 American Physical Society.