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Elastic Deformations in Thin Freestanding Ferroelectric Films
Author(s) -
Nair J.,
Lubomirsky I.
Publication year - 2002
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/1527-2648(20020806)4:8<604::aid-adem604>3.0.co;2-q
Subject(s) - materials science , silicon , substrate (aquarium) , ferroelectricity , thin film , composite material , stress (linguistics) , sputtering , ultimate tensile strength , clamping , buffer (optical fiber) , optoelectronics , nanotechnology , dielectric , mechanical engineering , telecommunications , linguistics , oceanography , philosophy , computer science , engineering , geology
We investigated mechanical stress in thin freestanding BaTiO 3 films prepared on bare silicon and on silicon, covered by a 120 nm thick, randomly oriented Al 2 O 3 buffer. Films prepared on bare silicon by RF sputtering are essentially stress‐free. However, they disintegrate after substrate removal. In contrast, the films prepared on the Al 2 O 3 buffer have high tensile stress, but retain their structural integrity after separation from the substrate. Substrate removal is accompanied by film corrugation; at the same time, the freestanding films resonate mechanically. This seeming contradiction can be understood on the basis of a recently developed theory of 2D clamping in thin ferroelectric films.