Paper AS+BI+NS-WeM10
Scanning Local Capacitance Measurements with High Spatial and Dielectric Resolution
Wednesday, November 2, 2011, 11:00 am, Room 102
| Session: |
Advances in Scanning Probe Microscopy |
| Presenter: |
Matthew Brukman, University of Pennsylvania |
| Authors: |
M.J. Brukman, University of Pennsylvania
S. Nanayakkara, University of Pennsylvania
D.A. Bonnell, University of Pennsylvania
|
| Correspondent: |
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Spatial variation of dielectric properties often dictates the behavior of devices ranging
from field effect transistors to memory devices to organic electronics, yet dielectric
properties are rarely characterized locally. We present methods of analyzing 2nd
harmonic-based local capacitance measurements achieved through non-contact atomic
force microscopy. Unlike contact-based methods, this technique preserves tip
shape and allows the same probe to realize high-resolution topographic imaging and
scanning surface potential imaging. We present an improved analysis of the electrical
fields between tip and sample, yielding high sensitivity to the capacitance-induced
frequency shift.
The techniques are applied to thin-film strontium titanate and mixed-phase self-
assembled monolayers to illustrate application to high dielectric constant hard materials
and lower dielectric constant organic films. Conversion from frequency shift signal to
dielectric constant κ is demonstrated on both samples, with sub-5 nm spatial resolution
and dielectric constant resolution between 0.25 and 1.