Traceable Nanoscale Measurements of High Dielectric Constant by Scanning Microwave Microscopy

Area of Science:

• Materials Science
• Electrical Engineering
• Metrology

Background:

• High dielectric constant (high-κ) materials are essential for advanced nano-electronic devices operating at high frequencies.
• Their performance is dictated by polarization, which is directly linked to relative permittivity (dielectric constant).

Purpose of the Study:

• To precisely quantify the dielectric constants of lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) at the nanoscale.
• To investigate and minimize uncertainties in dielectric constant measurements using scanning microwave microscopy (SMM).

Main Methods:

• Utilized scanning microwave microscopy (SMM) for nanoscale metrological quantification of dielectric constants in the GHz range.
• Developed novel approaches for correcting lateral dimension measurements on micro-capacitive structures, particularly for rough high-κ surfaces.
• Introduced an analytical expression for capacitance calculations that includes fringing electric field contributions.

Main Results:

• Determined dielectric constant values of εPZT = 445 and εPMN-PT = 641 around 3.6 GHz.
• Achieved combined relative uncertainties of 3.5% for PZT and 6.9% for PMN-PT.
• Demonstrated the critical role of capacitance calibration and accurate dimensional measurements in reducing uncertainty.

Conclusions:

• Established a metrological framework for accurately measuring high dielectric constants with controlled, low uncertainty.
• The developed methods are applicable to various high-κ materials used in high-frequency nano-electronic applications.