Scanning force microscope to determine interaction forces with high-frequency cantilever
AssigneesUniversity of Puerto Rico, Case Western Reserve University
InventorsFredy R. Zypman, Steve Eppell
Life of this patent
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Abstract
An apparatus and method for determining a force of interaction between a sample and a tip on a cantilever. The method uses a non-Hookian equation to model the cantilever as it is deflected by the force of interaction between the sample and the cantilever tip. The sample is positioned at a predetermined distance from the cantilever tip such that the cantilever is deflected by the force of interaction. The positions of a plurality of points on the cantilever are then rapidly measured and the force of interaction from the measured positions is then obtained using a non-Hookian model that accounts for higher order vibrational modes of the cantilever.
Claims12
A method for determining a force of interaction between a sample and a tip on a cantilever, comprising:
- positioning the sample and the cantilever tip in a predetermined distance from each other;
- rapidly measuring respective positions of a plurality of points on the cantilever as the cantilever is deflected by the force of interaction;
- modeling the cantilever with a non-Hookian model that accounts for higher order vibrational modes of the cantilever;
- and
- calculating the force of interaction from the measured positions of the plurality of points using the model.
A method for determining a force-distance curve for an interaction between a tip on a cantilever and a sample, comprising:
- positioning the sample and the cantilever tip in a predetermined distance from each other;
- rapidly measuring the respective positions of a plurality of points on the cantilever as the cantilever is deflected by the force of interaction;
- modeling the cantilever with a non-Hookian model that accounts for higher order vibrational modes of the cantilever for the predetermined distance;
- calculating the force of interaction from the measured positions of the plurality of points using the model thus determining one point of the force-distance curve;
- varying the predetermined distance by a preselected distance increment;
- and
- repeating the measuring, the modeling, the calculating, and the varying of a preselected number of times until the force-distance curve is determined.
An apparatus for determining a force of interaction between a sample and a tip on a cantilever, comprising:
- a positioning mechanism to position the tip at a known location in relation to the sample;
- a deflection measurer for determining rapidly deflection due to the force of interaction of a plurality of points on the cantilever;
- a processor for modeling the cantilever with a non-Hookian model accounting for higher order vibrational modes of the cantilever, and for calculating the force of interaction from the measured deflection of the plurality of points using the model of the cantilever;
- a memory for storing instructions for the processor to model the cantilever;
- and
- a controller for directing the positioning mechanism to position the tip at predetermined locations.
Dependencies are inferred from the claim text.