Rethinking Chip Cooling Methods

As the demand for powerful AI datacentre chips continues to rise, the challenge of managing heat generation becomes increasingly critical. To address this issue, several innovative cooling technologies are emerging, leveraging lasers and phonons to enhance thermal management.

One such development is the laser-based photonic cooling collaboration between Sandia National Laboratories and Maxwell Labs, a Minnesota-based startup. While lasers are commonly associated with heating, they can be utilized at specific light frequencies to target small, pure elements. This approach, already employed in quantum sensors and computers, has the potential to cool GPUs in AI datacentres by focusing laser light on localized hot spots.

According to Raktim Sarma, the lead physicist at Sandia, a significant portion of energy consumption in data centres is dedicated to cooling, with potential strain on local water resources. By utilizing photonic cold plates, which can complement traditional cooling systems, the extracted heat in the form of light can be recycled back into electricity.

The Maxwell cold plate, designed with gallium arsenide features, aims to channel laser light to specific hot spots. To maintain the cooling effect, the cold plate requires extremely pure layers of crystalline gallium arsenide. Initial modeling suggests that laser-based cooling systems could outperform traditional water-based methods in keeping chips at lower temperatures.

A research partnership between Maxwell Labs and Sandia will further develop and implement these laser-based cooling systems.

Exploring Phonon-Based Cooling

Another promising approach to address heat management in chips involves utilizing a new type of phonons, known as hyperbolic phonon-polaritons (HPhPs). Researchers at the University of Virginia (UVA) are pioneering this method using hexagonal boron nitride (hBN) to efficiently carry thermal energy away from the chip.

By harnessing HPhPs, which can transport heat at remarkable speeds, the UVA team is revolutionizing heat dissipation strategies. This innovative technique transforms heat into focused waves that swiftly travel across long distances, offering a new paradigm for temperature control at the nanoscale.

Meanwhile, researchers at the Advanced Science Research Centre at the CUNY Graduate Centre in New York are also exploring the use of hyperbolic phonon-polaritons. By incorporating a thin layer of graphene between hBN slabs, they aim to emit phonon-polaritons using electrical currents, a more cost-effective and efficient method compared to traditional laser-based approaches.

These advancements in phonon-based cooling technologies hold great promise for enhancing thermal management in AI datacentres and electronic devices, paving the way for more efficient and sustainable cooling solutions in the future.