Researchers from the Autonomous University of Barcelona and the United States have shown that heat transport has a behavior similar to that of a viscous fluid when studied at the nanometer scale. The discovery can help improve thermal behavior in electronic devices.
Scientists from the departments of Physics and Electronic Engineering of the Autonomous University of Barcelona (UAB) and the Birck Nanotechnology Center of Purdue University (USA) have studied the heating of small current lines located on a silicon substrate, simulating the behavior of current transistors. The results are published in Nature Communications. In this paper we show how these metal lines are heated in a way that can not be explained by the laws that govern the behavior of heat in our daily experience.
Through a theoretical model, developed by the students Pol Torres and Àlvar Torello, under the direction of the professors of the UAB Francisco Javier Álvarez and Xavier Cartoixà, it has been possible to explain the experimental observations, showing that the heat presents difficulties to turn when it passes from the metal to the substrate, as would occur in the case of a viscous fluid coming out of a conduit. This phenomenon makes it difficult to cool the metal line and consequently its temperature increases to values not explained by current models.
During operation, the most active parts of an electronic device can accumulate a lot of thermal energy in very localized areas, called hot spots. This accumulation of energy can be very detrimental to the proper functioning of the device, and represents a bottleneck that limits the performance of current processors. According to the authors, this discovery opens the door to a better optimization of the thermal behavior of these devices, since the proposed model represents a significant improvement over the theoretical models currently handled by device engineers, based on the Fourier law .
This results also represent a new verification of the so-called theory of extended thermodynamics, developed in the 90s by UAB professors David Jou and José Casas.