High resolution secondary ion mass spectrometry depth profiling using continuous sample rotation and its application to superlattice and delta-doped sample analysis

Abstract

We report the development of secondary ion mass spectrometry (SIMS) with continuous sample rotation to achieve high resolution that is independent of depth during compositional and dopant sputter depth profiling. Sample rotation reduces the ion beam-induced surface roughness that often limits the depth resolution in SIMS. To illustrate the effects of sample rotation on SIMS analysis, measurements both with and without rotation were performed on a molecular beam epitaxy grown AlGaAs/GaAs superlattice with 100 periods and 5-nm-thick layers, and a boron delta-doped (atomically planar) Si sample, with dopant concentrations from 1016–1021 atoms/cm3 at depths of 0.5–2.0 μm.