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Piezoelectric response characterization using atomic force microscopy with standard contact-mode imaging

Sharath Sriram 1Madhu Bhaskaran 1Ken T. Short 2Glenn I. Matthews 3Anthony S. Holland 1

1. RMIT University, Sch. of Elec. and Comp. Engg., Microelectronics and Materials Technology Centre (RMIT), GPO Box 2476V, Melbourne, Victoria, Melbourne 3001, Australia
2. Australian Nuclear Science and Technology Organisation, Institute of Material Science and Engg. (ANSTO), PMB 1, Menai, New South Wales, Sydney 2234, Australia
3. RMIT University, Sch. of Elec. and Comp. Engg., Sensor Technology Laboratory (RMIT), GPO Box 2476V, Melbourne, Victoria, Melbourne 3001, Australia


Standard atomic force microscopes (AFM) require extensive modifications to operate as piezoresponse force microscopes. This paper discusses a technique for observing and quantifying piezoelectric response of thin films, using standard AFMs. The technique has been developed and verified using strontium-doped lead zirconate titanate (PSZT) thin films, which are known for their high piezoelectric response. Quantification of the electro-mechanical voltage co-efficient d33 (in pm/V) is directly made based on the applied peak-to-peak voltage and the corresponding peak-to-peak displacement in the obtained scan image.

Under the proposed technique the AFM is configured in contact mode, where the silicon nitride tip is set to follow the film displacement at a single point. A known sinusoidal voltage is applied across the film and the displacement determined as a function of time, rather than the typical AFM measurement of displacement versus tip position. The resulting raster image contains several bands, which are directly related to the AFM scan frequency and the applied sinusoidal voltage and its frequency.

Different combinations of the AFM scan frequency and the applied sinusoid frequency have been used to characterize the PSZT thin films. The films analyzed were deposited under different conditions and were of varying thickness, on gold and platinum coated silicon substrates. Large displacements have been observed for the PSZT thin films, which correspond to d33 values above 550 pm/V. These results have also been verified by nano-indentation based piezoresponse tests. The effect of positioning the tip away from the top electrode of samples has been studied, with results in agreement with expected decrease in the electric field strength with distance from the top electrodes.


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Presentation: Oral at E-MRS Fall Meeting 2007, Symposium J, by Sharath Sriram
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-04-30 14:39
Revised:   2009-06-07 00:44