Interface and overlayer structure of epitaxial CaF{sub 2} thin films on Si(111) :.
Using X-ray scattering techniques we investigated a 50 Angstrom thick CaF{sub 2} film, epitaxially grown on a Si(111) substrate. The CaF{sub 2} overlayer exhibits an incommensurately modulated structure parallel to the heterointerface, consisting of a triangular network of discommensurations, which separate domains with two different Ca site occupations H3 and T4. The 2D spatial modulation of the overlayer is induced by the competition between the strong covalent-like Ca-Si bonding at the interface and the ionic Ca-F bonding in the film. Remarkably, the in-plane periodic lattice distortion generated at the interface propagates many atomic layers through the CaF{sub 2} film. Specular reflectivity and standing wave measurements suggest that the CaF{sub 2}-Si interface is unstable towards the formation of an intermediate CaSi{sub 2} layer. In situ temperature-dependent strain measurements revealed that the strong interfacial Ca-Si bonding prevents a complete in-plane lattice relaxation up to 700 C while the overlayer expands considerably normal to the interface.
- Research Organization:
- Argonne National Laboratory (ANL)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 937789
- Report Number(s):
- ANL/MSD/JA-19761
- Journal Information:
- Physica B, Journal Name: Physica B Journal Issue: 1-4 ; Apr. 1996 Vol. 221; ISSN 0921-4526; ISSN PHYBE3
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Two-dimensional structural modulation in epitaxial CaF[sub 2] overlayers on Si(111)
Structure of the Si(111)-CaF/sub 2/ interface
Epitaxial growth of laminar crystalline silicon on CaF{sub 2}
Journal Article
·
Mon Apr 11 00:00:00 EDT 1994
· Physical Review Letters; (United States)
·
OSTI ID:5112667
Structure of the Si(111)-CaF/sub 2/ interface
Journal Article
·
Mon Oct 10 00:00:00 EDT 1988
· Phys. Rev. Lett.; (United States)
·
OSTI ID:6794455
Epitaxial growth of laminar crystalline silicon on CaF{sub 2}
Journal Article
·
Mon Aug 28 00:00:00 EDT 2000
· Applied Physics Letters
·
OSTI ID:20217409