Transient effects induced through ripple topography growth during Cs+ depth profile analysis of Si at high incidence angles

Cs+ depth profiling of Si at high incidence angles introduces additional transient effects and significantly longer transient widths (up to 30 nm in depth). Analysis of a well-defined delta layered Si structure with a 250 eV Cs+ ion beam incident at 75°, reveals that the enhancement of these transient effects are accompanied by: (a) a sputter rate reduction, (b) ripple topography formation and (c) a continually increasing implanted Cs concentration over the first ∼30 nm. Steady state sputtering ensues after this depth with no further roughening. These trends indicate that that the enhanced transient effects are initiated through surface roughening, which reduces sputter rates. A reduction in the sputter rate allows for more Cs to be retained within the near surface region, which in turn enhances negative secondary ion yields.