High-Accuracy Contact Resistance Measurement Method for Liquid Metal by Considering Current-Density Distribution in...

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Liquid metals (LMs), particularly Ga-based ones, are vital for stretchable electronics due to their conductivity.
• Accurate characterization of electrical properties, like contact resistance (Rc), is essential for device performance.
• Conventional transfer length method (TLM) measurements have limitations when object and electrode resistances are comparable.

Purpose of the Study:

• To develop and validate a precise method for determining contact resistance (Rc) between galinstan and copper electrodes.
• To address the limitations of conventional TLM by considering current-density distribution.
• To enable more reliable development of stretchable electronic devices utilizing liquid metals.

Main Methods:

• Proposed a modified TLM by applying current to individual measuring electrodes, unlike conventional outer electrode application.
• Utilized simulations to analyze current-density distribution and its impact on resistance measurements.
• Compared results from the new method with conventional TLM to highlight discrepancies.

Main Results:

• Found that sheet resistance of galinstan cannot be ignored in TLM measurements.
• The new method accurately captured the entire contact resistance component, unlike conventional methods (<10%).
• Achieved a low contact resistivity (ρc) of 0.115 mΩ·mm², significantly lower than solders.

Conclusions:

• Accurate Rc measurement requires applying current to each electrode and considering volume resistances.
• The developed method provides a more reliable way to measure LM contact resistance.
• This research facilitates advancements in stretchable electronics by offering precise electrical interface characterization.