Calcium fluoride on Si(001): Adsorption mechanisms and epitaxial growth modes

Journal Article · Fri Jul 15 00:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.72.045448· OSTI ID:20719172

Pasquali, L; Selvaggi, G ^[1]; Suturin, S M; Ulin, V P; Sokolov, N S ^[2]; Giglia, A; Nannarone, S ^[1]; Mahne, N; Pedio, M ^[3]

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1. Dipartimento di Ingegneria dei Materiali e dell'Ambiente, Universita di Modena e Reggio Emilia, Via Vignolese 905, 41100-Modena (Italy)
2. Ioffe Physical-Technical Institute, RAS, Solid State Optics Department, 26 Polytechnicheskaya str., 194021 St. Petersburg (Russian Federation)
3. INFM-CNR-TASC Laboratory, s.s. 14, km 163.5 in AREA Science Park, 34012 Basovizza, TS (Italy)

Growth of CaF{sub 2} on Si(001) is studied as a function of the substrate temperature during deposition for coverages from fraction of a monolayer (ML) up to several monolayers. Structural and morphological studies using atomic force microscopy, low-energy electron diffraction, and reflection high-energy electron diffraction are combined with measurements of core-level photoemission and x-ray absorption. Bonding between CaF{sub 2} molecules and Si(001) substrates is followed by monitoring core-level shifts and x-ray absorption line shape. It is found that a dissociative reaction occurs at high deposition temperatures ({approx}750 deg. C), giving rise to a 1-ML-thick uniform wetting layer, which is bonded with the substrate through Ca atoms. This wetting layer changes the surface periodicity from double domain 2x1+1x2 to single domain 3x1. Three-dimensional CaF{sub 2} elongated islands develop on top of the wetting layer, with their (110) planes parallel to the Si surface plane. At temperatures below 600 deg. C no dissociative reaction takes place for CaF{sub 2}; nanodimensional islands develop in the form of rectangular-based huts. The crystallographic orientation of these islands is parallel to that of the Si(001) substrate. The data are compared to results obtained on CaF{sub 2} deposited on Si(111)

• OSTI ID: 20719172
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevB.72.045448; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ADSORPTION
ATOMIC FORCE MICROSCOPY
ATOMS
CALCIUM FLUORIDES
CRYSTAL GROWTH
CRYSTALLOGRAPHY
DEPOSITION
DISSOCIATION
ELECTRON DIFFRACTION
LAYERS
MOLECULAR BEAM EPITAXY
MOLECULES
MORPHOLOGY
NANOSTRUCTURES
PERIODICITY
PHOTOEMISSION
REFLECTION
SILICON
SUBSTRATES
SURFACES
X RADIATION