Determination of polarization profiles inside ferroelectric thin films using the laser intensity modulation method

Gerald Gerlach; Thilo Sandner; Gunnar Suchaneck

doi:10.1117/12.483784

22 July 2003 Determination of polarization profiles inside ferroelectric thin films using the laser intensity modulation method

Gerald Gerlach, Thilo Sandner, Gunnar Suchaneck

Author Affiliations +

Proceedings Volume 5045, Testing, Reliability, and Application of Micro- and Nano-Material Systems; (2003) https://doi.org/10.1117/12.483784
Event: NDE for Health Monitoring and Diagnostics, 2003, San Diego, California, United States

Abstract

In this work, the laser intensity modulation method (LIMM) is applied to the investigation of the polarization distribution profile inside ferroelectric thin films. Here, a sinusoidal thermal wave is generated by a laser, thus causing a pyroelectric current. This current is influenced by the frequency and, hence, the penetration depth of the thermal wave inside the thin film as well as by the polarization state of this layer. The spatial polarization profile is then determined from the pyroelectric current spectrum by inverse solution of the appropriate FREDHOLM integral equation. Mathematically considered, this represents an ill-posed problem, which usually leads to numerically unstable solutions with an often severely disturbed waveform. Taking both profiles with larger gradients and superimposed noise at the pyroelectric current spectra into account, a TIKHONOV regularization method has to be employed to accomplish numerically stable and reliable results for the reconstructed polarization profiles. Based on the consideration of different typical polarization profiles, the influence of various regularization approaches was investigated, which determine the uncertainty of the reconstruction result. This work explains the effects of uncertainties of measurement due to data noise, non-optimal regularization parameters, material parameter variations and deviations of the thermal model and the influence of uncertainties due to non-optimal model assumptions. It will be shown that the lacking knowledge of precise thin film material parameters and noise inside the measuring setup represent the most decisive uncertainty sources for the LIMM method to determine polarization thickness profiles inside ferroelectric thin films.

Citation Download Citation

Gerald Gerlach, Thilo Sandner, and Gunnar Suchaneck "Determination of polarization profiles inside ferroelectric thin films using the laser intensity modulation method", Proc. SPIE 5045, Testing, Reliability, and Application of Micro- and Nano-Material Systems, (22 July 2003); https://doi.org/10.1117/12.483784

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available