What is a Surface Resistivity Electrode?

Electrodes are conductors that permit a flow of electricity in and out of an object. The application range for electrodes is vast, and various different types exist for distinct purposes. The surface resistivity electrode is one of these unique formats.

As the name implies, a surface resistivity electrode is used to measure the surface resistivity and conductivity of various materials. Surface resistivity electrodes are commonly used to record sheet resistance when measuring the conductivity of biological tissues, polymers, and advanced materials.

This article will explore the basics of surface resistivity and will highlight the benefits of nanopatterned electrodes in optimising the electrical properties of component interfaces.

What is Surface Resistivity?

Surface resistivity defines the resistance to leakage current along the surface of insulating materials. The physical unit of measurement is Ohm (Ω). Surface resistivity and surface resistance are often confused because the legitimate unit of surface resistance is also Ohm. The main difference is that surface resistivity is measured in ohms squared.

To measure surface resistivity, electrodes are placed parallel to each other along the insulator material’s surface, allowing the four ends of the electrodes to form a square. This is why Ohms per square is often used to report surface resistivity measurements. It is important to note that surface resistivity should remain stable, regardless of the instruments used to measure it. 

In short, the higher the surface resistivity, the lower the leakage current and thus the lower the material’s conductivity. 

Why Is Surface Resistivity Important?

Surface resistivity is measured in material to test how capable the material is of emitting electrostatic charges. An electrostatic charge occurs when there is an excess or deficiency of electrons on a surface after the friction between two materials.

It is essential to measure surface resistivity because, in some cases, electrical components can be highly sensitive to electrostatic discharge (ESD). If the ESD is too low or too high, the damage caused can be severe. Permanent damage to any components can, of course, be extremely costly for any company. Machinery may need to be repaired or replaced, which would grind production to a halt and lead to expensive downtime periods.

Downtime is a particularly galling pain point currently given the ongoing supply chain disruptions. Few companies can afford lead times to be further extended.

What Is A Patterned Electrode?

Patterned, or printed, electrodes are small measurement devices produced by printing different inks onto plastic or ceramic substrates. At Platypus Technologies, we use these electrodes to measure sheet resistance, develop chemical sensors, and conduct electrochemical experiments. 

To produce a patterned electrode, we employ electron beam physical vapor deposition (EBPVD) to place thin gold coating onto glass. The substrate is then patterned using photolithography techniques. These electrodes can be used in MEMS biosensors (bioMEMS) and chemical sensor chips.

We specialize in custom coatings for various applications, and our processing methods have allowed us to develop research-grade gold patterned electrodes, including high-performance resistivity electrodes. Advantages of our products include:

• Low surface roughness
• Outstanding reproducibility
• Transparent glass substrates enable high-quality image analysis
• High purity gold that does not require pre-cleaning

Our surface resistivity electrodes are the ideal solution for mitigating hazardous ESD phenomena in critical components. With our proprietary processing capabilities and dedicated attention to customer satisfaction, we are uniquely positioned to provide reliable nanopatterned electrodes designed to individual specifications.

Please contact us today if you would like more information on any of our patterned electrodes.