New ultra-strong material for microchip sensors

Researchers at Delft University of Technology have developed amorphous silicon carbide (a-SiC) that could impact the world of material science. Beyond its strength, the material demonstrates mechanical properties that are necessary for vibration isolation on a microchip. Amorphous silicon carbide is therefore suitable for making ultra-sensitive microchip sensors. Amorphous silicon carbide has a range of potential applications, ranging from advanced solar cells to DNA sequencing technologies. The advantages of this material’s strength combined with its scalability make it promising.

“To better understand the crucial characteristic of ‘amorphous’, think of most materials as being made up of atoms arranged in a regular pattern, like an intricately built Lego tower. These are termed as ‘crystalline’ materials, like, for example, a diamond. It has carbon atoms perfectly aligned, contributing to its famed hardness,” said Assistant Professor Richard Norte.

However, amorphous materials are akin to a randomly piled set of Lego, where atoms lack consistent arrangement. But this randomisation does not result in fragility, as amorphous silicon carbide has a tensile strength of 10 GigaPascal (GPa). “To grasp what this means, imagine trying to stretch a piece of duct tape until it breaks. Now if you’d want to simulate the tensile stress equivalent to 10 GPa, you’d need to hang about 10 medium-sized cars end to end off that strip before it breaks,” Norte said.

The researchers used an innovative method to test the material’s tensile strength; instead of traditional methods that might introduce inaccuracies from the way the material is anchored, they turned to microchip technology. By growing the films of amorphous silicon carbide on a silicon substrate and suspending them, the researchers leveraged the geometry of the nanostrings to induce high tensile forces. By fabricating many such structures with increasing tensile forces, the researchers observed the point of breakage.

“Nanostrings are fundamental building blocks, the very foundation that can be used to construct more intricate suspended structures. Demonstrating high yield strength in a nanostring translates to showcasing strength in its most elemental form,” Norte said.

Amorphous silicon carbide is also scalable, as it can be produced at wafer scales, offering large sheets of material. “With amorphous silicon carbide’s emergence, we’re poised at the threshold of microchip research brimming with technological possibilities,” Norte said.

The research findings have been published in the journal Advanced Materials.

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