All of our most-used electronic devices rely on increasingly smaller microchips. One of the biggest hurdles to putting more circuits and power onto a smaller chip is managing the heat. As chips become smaller, heat increases exponentially. Not only are there more transistors in a given area — which generates more heat in a small space — but they also are closer together, making it harder for heat to dissipate.
A research team explored an emerging type of material with the potential to keep chips cool as they continue shrinking in size. Called “low-k” dielectrics, electrical insulation materials minimize electrical crosstalk in chips. By steering current to eliminate signal interference, low-k dielectrics make all electronics possible. Ideally, this material type also could pull damaging, electrical current-generated heat away from the circuitry. But because low-k materials have very low thermal conductivity, they have been previously unable to manage heat.
Scientists have been in search of a low-k dielectric material that can handle the heat transfer and space issues inherent at much smaller scales. Using two-dimensional (2D) covalent organic frameworks (COFs), the team developed high-quality, porous COF thin films that finally solve the heat problem. Not only is the material low-k but it also has high thermal conductivity. The team is currently applying this new material class to meet the requirements of miniaturizing transistors on a dense chip.
The team took sheets of polymer that are one atom thick — called 2D — and controlled their properties by layering the sheets in a specific architecture. COFs show both low-k properties and thermal conductivity as a consequence of their 2D layer architectures and porous structures.
The researchers are exploring this new class of materials for applications such as chemical sensing. The materials can be used to determine (or sense) what chemicals and how much of those chemicals are in the air. Knowing about the chemicals in the air, researchers can optimize food storage, transport, and distribution to reduce global food waste.