Combining different materials and altering electrode design allows the capacitors to survive temperatures as high as 300 °C. (Courtesy of Fraunhofer IMS)

Fraunhofer Researchers Debut Heat-Resistant Capacitor

May 23, 2017
Increased surface area on the electrodes and the combination of certain materials improves the performance of this capacitor at high temperatures.

A research team from Fraunhofer IMS  announced development of a capacitor with a high dielectric constant and heat resistance up to 300°C. The technology has a potential to improve the performance of semiconductor electronic components, even in applications that generate high heat.

The technology could simplify electronic design by reducing the need for cooling fins and ventilators. This could improve size and space constraints of electronics without compromising their performance in ultra-hot environments.

The team used a tantalum pentoxide dielectric between its positive and negative electrodes. As a semiconductor with a high dielectric constant (k), tantalum pentoxide has a higher concentration of charge carriers than a silicon dioxide dielectric, and can store more charge across a thinner layer with significantly less current leakage. The team also used electrically conductive silicon and ruthenium in their electrodes to improve the capacitor’s overall heat resistance.

The scientists then looked to increase the capacitance by altering the construction of the electrodes. By etching tiny holes in the electrode surface, they could increase the surface area for higher flux across the capacitor. The dielectric could also fill in the holes to be more resilient against heat. Though the dielectric is thicker, it does not require a wider distance between the electrode plates, so the alteration did not significantly lower the capacitance.

And because the tantalum pentoxide is a metal-oxide semiconductor, it could be deposited with a single-atom thickness. “This makes production very flexible,” says Dorothee Dietz, leading scientist of the team at Fraunhofer IMS. “The manufacturer can produce components exactly according to the customer’s specifications without having to change the flow of the process.”

The team expects that the technology will be useful to improve the performance in both active and passive electronic components, even in high friction applications that generate high heat.

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