Open AccessElectrode size and boundary condition independent measurement of the effective piezoelectric coefficient of thin films
Author(s) -
Mark Stewart,
Serban Lepadatu,
L.N. McCartney,
Markys G. Cain,
Louise Wright,
Jason Crain,
D. M. Newns,
Glenn Martyna
Publication year - 2015
Publication title -
apl materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.571
H-Index - 60
ISSN - 2166-532X
DOI - 10.1063/1.4907954
Subject(s) - piezoelectricity , materials science , electrode , finite element method , thin film , discontinuity (linguistics) , bending , piezoelectric coefficient , boundary value problem , enhanced data rates for gsm evolution , interferometry , composite material , optics , mathematical analysis , physics , thermodynamics , nanotechnology , mathematics , telecommunications , quantum mechanics , computer science
The determination of the piezoelectric coefficient of thin films using interferometry is hindered by bending contributions. Using finite element analysis (FEA) simulations, we show that the Lefki and Dormans approximations using either single or double-beam measurements cannot be used with finite top electrode sizes. We introduce a novel method for characterising piezoelectric thin films which uses a differential measurement over the discontinuity at the electrode edge as an internal reference, thereby eliminating bending contributions. This step height is shown to be electrode size and boundary condition independent. An analytical expression is derived which gives good agreement with FEA predictions of the step height
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