Progress in Traceable Nanoscale Capacitance Measurements Using Scanning Microwave Microscopy

Area of Science:

• Electrical Metrology
• Materials Science
• Nanotechnology

Background:

• Reference samples are crucial for calibrating nanoscale electrical measurements in techniques like scanning microwave microscopy (SMM).
• Current calibration samples lack established traceability, limiting the reliability of capacitance and dielectric constant measurements.
• Uncertainty in these measurements hinders accurate material characterization and device performance evaluation.

Purpose of the Study:

• To investigate and quantify error sources affecting capacitance measurements on reference calibration samples.
• To establish a comprehensive uncertainty budget for traceable capacitance measurements in SMM.
• To propose improvements for classical calibration methods and suggest new designs for traceable reference standards.

Main Methods:

• Detailed analysis of potential error sources impacting capacitance measurements on reference samples.
• Development of a comprehensive uncertainty budget incorporating various influencing factors.
• Experimental capacitance measurements supported by numerical simulations.
• Evaluation of uncertainty contributions across different capacitance values and sample dimensions.

Main Results:

• A combined uncertainty of 3% (at one standard deviation) was achieved for capacitance measurements from 0.2 fF to 10 fF.
• This uncertainty level is attainable even with unshielded probes.
• The relative importance of different uncertainty sources was found to vary with measured capacitance values and dimensions.

Conclusions:

• The study provides a traceable uncertainty budget for nanoscale capacitance measurements, significantly enhancing measurement reliability.
• The findings offer practical improvements to existing scanning microwave microscopy calibration techniques.
• New designs for traceable reference standards are proposed, paving the way for more accurate dielectric property measurements.