Non-uniform Thermal Conductivity in Nanoscale Multiple Hotspot Systems

TL;DR

This study investigates how non-uniform thermal conductivity affects heat dissipation in nanoscale hotspot systems, revealing that spatial variations can significantly enhance thermal transport and offering new insights for thermal management in electronics.

Contribution

It introduces the concept of local thermal conductivity in nanoscale hotspots and demonstrates how hotspot spacing influences heat flux, challenging the assumption of uniform thermal transport.

Findings

Maximum thermal conductivity exceeds uniform case by 27%.

Reducing hotspot spacing increases heat flux by up to 40%.

Non-uniform phonon emission enhances heat dissipation.

Abstract

Understanding nanoscale hotspot thermal transport is crucial in electronic devices. Contrary to common perception, recent experiments show that closely spaced nanoscale multiple hotspots can enhance heat dissipation. Here, the thermal transport in nanoscale multiple hotspot systems is investigated by solving the phonon Boltzmann transport equation. The local thermal conductivity is proposed to describe the non-uniform spatial distribution of heat transport capability in nanoscale multiple hotspot systems. The maximum value exceeds the uniform heating case by up to 27%, which is attributed to the spatially varying fraction of unscattered phonons emitted from hotspots. Moreover, the effects and mechanisms of hotspot spacing on thermal transport are investigated, showing that reducing the hotspot spacing can enhance the heat flux by up to 40%. This work challenges the conventional view that thermal transport capability is spatially uniform throughout the system and provides fundamental insights for thermal management in high-power-density integrated circuits.