Computer processors have continued to shrink down to nanometer sizes where there can be billions of transistors on a single chip. This phenomenon is described under Moore's Law, which predicts that the number of transistors on a chip will double about every two years. Each generation of smaller chips helps make computers faster, more powerful, and able to do more work. But that means they're generating more heat.

A schematic of a computer chip with a hot spot (bottom); an electron microscope image of defect-free boron arsenide (middle); and electron diffraction patterns in boron arsenide. (Hu Research Lab/UCLA Samueli)

Managing heat in electronics has increasingly become one of the biggest challenges in optimizing performance. High heat is an issue for two reasons. First, as transistors shrink in size, more heat is generated within the same footprint. This high heat slows down processor speeds; in particular, at hot spots on chips where heat concentrates and temperatures soar. Second, a lot of energy is used to keep those processors cool. If CPUs did not get as hot in the first place, then they could work faster and require much less energy to keep them cool.

To address hot spots in computer chips that degrade their performance, a new semiconductor material — defect-free boron arsenide — was developed that is more effective at drawing and dissipating waste heat than any other known semiconductor or metal materials. This could potentially revolutionize thermal management designs for computer processors and other electronics, or for light-based devices like LEDs.

The defect-free boron arsenide has a record-high thermal conductivity — more than three times faster at conducting heat than currently used materials such as silicon carbide and copper. Heat that would otherwise concentrate in hot spots is quickly flushed away.

The material could be integrated into current manufacturing processes because of its semiconductor properties and the demonstrated capability to scale up this technology. It could replace current state-of-the-art semiconductor materials for computers. In addition to the impact for electronic and photonics devices, the work also revealed new fundamental insights into the physics of how heat flows through a material.

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