SIMS response functions for MBE grown delta layers in silicon

Abstract

SIMS response functions and depth resolution parameters have been measured using O 2 + primary ions at normal incidence and 45°, for a range of silicon MBE grown epilayers containing ultrathin buried layers or “deltas” doped with B. Growth and decay slopes and differential shifts are shown to be species dependent. For B, the depth resolution is superior at normal incidence, and has a linear energy dependence for both normal incidence and 45°. The differential shift is dependent on the depth of a feature with respect to the final crater depth, and is due to erosion rate changes across the pre-equilibrium region, species dependent probe-induced mass transport, and the effect of the residual altered layer on crater depth measurement.