Development of a programmable standard of ultra-low capacitance values

Area of Science:

• Electrical Metrology
• Nanoscale Measurement Science

Background:

• Accurate calibration of precision capacitance bridges is crucial for advanced electronic measurements.
• Existing standards may lack the resolution for ultra-low capacitance ranges.
• Development of novel metrological tools is needed for nanoscale applications.

Purpose of the Study:

• To develop and characterize an ultra-low value programmable capacitance standard.
• To enable calibration of commercial precision capacitance bridges in the 10 aF to 0.1 pF range.
• To assess and mitigate sources of uncertainty in the capacitance standard.

Main Methods:

• Development of a programmable coaxial multiplexer (mux) to connect ultra-low value capacitance standards in parallel.
• Realization and characterization of the programmable capacitance standard.
• Calibration of Andeen-Hagerling AH2700A bridges using the developed standard at 1 kHz.
• Evaluation of parasitic effects and stray impedances as sources of uncertainty.

Main Results:

• The programmable capacitance standard successfully generates decadic capacitances from 10 aF to 0.1 pF.
• Calibration of precision capacitance bridges achieved a maximum uncertainty of 0.8 aF across the entire range.
• Parasitic effects were evaluated, and methods to overcome them were discussed.

Conclusions:

• The developed programmable capacitance standard offers a reliable method for calibrating precision capacitance bridges at ultra-low values.
• The standard's performance supports its integration with atomic force microscopes (AFMs) and probe stations for quantitative capacitance measurements.
• Further research can refine uncertainty reduction techniques for enhanced metrological applications.