Instruction manual

Electric Force (EFM) Imaging
Electric Force Microscopy Overview
Rev. B MultiMode SPM Instruction Manual 241
Figure 14.1b EFM LiftMode principles
Figure 14.1c EFM probe tip holder, top and bottom view (left to right)
14.1.1 Electric Field Gradient Imaging Overview
Electric field gradient imaging is a technique which measures variations in the electric field
gradient above a sample. The sample may be conducting, nonconducting, or mixed. Since the
electric field gradient is also shaped by the surface topography (e.g. sharp points on the surface
concentrate the field gradient), large differences in topography can make it difficult to distinguish
electric field variations. In general, the best samples for electric field gradient imaging are samples
that have applied voltages of roughly 1V or more and samples with fairly smooth topography.
Samples with insulating layers (passivation) on top of conducting regions may also be good
candidates for electric field gradient imaging.
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Force Gradient Scope Data
Topographic Scope Data
(Main scan)
(Interleave scan)
Electric Fields
Cantilever measures surface topography on first (main) scan.
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Cantilever ascends to lift scan height.
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Cantilever follows stored surface topography at the lift height above sample
while responding to electric influences on second (interleave) scan.
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