Si1-x Ge x /Si Interface Profiles Measured to Sub-Nanometer Precision Using uleSIMS Energy Sequencing

R J H Morris; T P A Hase; A M Sanchez; G Rowlands

doi:10.1007/s13361-016-1439-4

Si1-x Ge x /Si Interface Profiles Measured to Sub-Nanometer Precision Using uleSIMS Energy Sequencing

J Am Soc Mass Spectrom. 2016 Oct;27(10):1694-702. doi: 10.1007/s13361-016-1439-4. Epub 2016 Jul 21.

Authors

R J H Morris^{1

2}, T P A Hase³, A M Sanchez³, G Rowlands³

Affiliations

¹ University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK. r.morris@warwick.ac.uk.
² , IMEC, Kapeldreef 75, B-3001, Leuven, Belgium. r.morris@warwick.ac.uk.
³ University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.

PMID: 27444703
DOI: 10.1007/s13361-016-1439-4

Abstract

The utility of energy sequencing for extracting an accurate matrix level interface profile using ultra-low energy SIMS (uleSIMS) is reported. Normally incident O2 (+) over an energy range of 0.25-2.5 keV were used to probe the interface between Si0.73Ge0.27/Si, which was also studied using high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). All the SIMS profiles were linearized by taking the well understood matrix effects on ion yield and erosion rate into account. A method based on simultaneous fitting of the SIMS profiles measured at different energies is presented, which allows the intrinsic sample profile to be determined to sub-nanometer precision. Excellent agreement was found between the directly imaged HAADF-STEM interface and that derived from SIMS. Graphical Abstract ᅟ.

Keywords: SIMS; Si/Si1-x Ge x; Ultra low energy depth profiling.