title: Designing a standard for strain mapping: HR-EBSD analysis of SiGe thin film structures on Si.
abstract: Patterned SiGe thin film structures, heteroepitaxially deposited on Si substrates, are investigated as potential reference standards to establish the accuracy of high resolution electron backscattered diffraction (HR-EBSD) strain measurement methods. The proposed standards incorporate thin films of tetragonally distorted epitaxial Si₁-xGex adjacent to strain-free Si. Six films of three different nominal compositions (x=0.2, 0.3, and 0.4) and various thicknesses were studied. Film composition and out-of-plane lattice spacing measurements, by x-ray photoelectron spectroscopy and x-ray diffraction, respectively, provided independent determinations of film epitaxy and predictions of tetragonal strain for direct comparison with HR-EBSD strain measurements. Films assessed to be coherent with the substrate exhibited tetragonal strain values measured by HR-EBSD identical to those predicted from the composition and x-ray diffraction measurements, within experimental relative uncertainties of order 2%. Such films thus provide suitable prototypes for designing a strain reference standard.
authors.affiliation: Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. Electronic address: mark.vaudin@nist.gov.
authors.forename: M D
authors.initials: MD
authors.lastname: Vaudin
authors.affiliation: Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Osborn
authors.affiliation: Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Friedman
authors.affiliation: Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Gorham
authors.affiliation: 3D Interconnect Division, SEMATECH, Albany, NY 12203, USA.
authors.forename: V
authors.initials: V
authors.lastname: Vartanian
authors.affiliation: Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Cook
keywords: EBSD; Electron backscattered diffraction; Epitaxial SiGe–Si; Standard; Strain measurement