Scanning kelvin microprobe system and process for analyzing a surface
First Claim
1. A scanning Kelvin microprobe system for analyzing a surface of a sample, the system comprising:
- a tip with a predetermined work function for exploring a surface of the sample, and for extracting Kelvin current from the local capacitor formed between the tip and the sample;
a scan table for placing the sample thereon;
a micropositioner for moving the scan table in x and y directions;
a piezoelectric translation stage attached to the scan table for moving the sample in the z direction for maintaining a constant sample-tip distance;
a charge amplifier for converting the Kelvin current extracted by the tip into a voltage;
a first lock-in amplifier tuned at a first frequency for measuring the voltage and generating a contact potential difference image signal;
a second lock-in amplifier tuned at a second frequency for monitoring sample-tip distance and for generating a topographic image signal, the second frequency being above the first frequency; and
a controller for controlling the micropositioner.
1 Assignment
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Accused Products
Abstract
A scanning Kelvin microprobe (SKM) system capable of measuring and analyzing surface characteristics of samples is provided. Also provided is a process of measuring and analyzing surface characteristics of samples. Further, there are provided uses of the SKM system in measuring and analyzing surface characteristics of conductors, semiconductors, insulators, chemicals, biochemicals, photochemicals, chemical sensors, biosensors, biochemical microarrays, microelectronic devices, electronic imaged devices, micromachined devices, nano-devices, corroded materials, stressed materials, coatings, adsorbed materials, contaminated materials, oxides, thin films, and self assembling monolayers.
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Citations
15 Claims
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1. A scanning Kelvin microprobe system for analyzing a surface of a sample, the system comprising:
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a tip with a predetermined work function for exploring a surface of the sample, and for extracting Kelvin current from the local capacitor formed between the tip and the sample;
a scan table for placing the sample thereon;
a micropositioner for moving the scan table in x and y directions;
a piezoelectric translation stage attached to the scan table for moving the sample in the z direction for maintaining a constant sample-tip distance;
a charge amplifier for converting the Kelvin current extracted by the tip into a voltage;
a first lock-in amplifier tuned at a first frequency for measuring the voltage and generating a contact potential difference image signal;
a second lock-in amplifier tuned at a second frequency for monitoring sample-tip distance and for generating a topographic image signal, the second frequency being above the first frequency; and
a controller for controlling the micropositioner. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 15)
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9. A process for analyzing a surface of a sample using a scanning Kelvin microprobe system, comprising the steps of:
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placing a sample on a scan table;
exploring a surface of the sample with a tip having a predetermined work function;
extracting Kelvin current from a local capacitor formed between the tip and the sample;
amplifying the Kelvin current extracted by the tip;
measuring the Kelvin current and generating a contact potential difference signal using a first lock-in amplifier tuned at a first frequency; and
monitoring distance between the sample and the tip and generating a topographic image signal using a second lock-in amplifier tuned at a second frequency, the second frequency being above the first frequency. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification