Measuring heat transport in electronic devices over small length scales

Abstract

High current operation is often desirable in electronic devices, as it affects a variety of essential aspects such as switching speed in transistors, sensitivity in sensors, and light output in light-emitting devices. High currents, however, can lead to premature device failure or the degradation of device performance, as the inherent increase in device operating temperature can degrade materials/junctions, increase leakage, or lower mobility. In an effort to characterize the heat transport in electronic devices near the region where the heat is generated and dissipated, we have implemented a frequency-domain thermoreflectance system that allows for the characterization of thermal transport in prototype devices, with the end goal of finding avenues to optimize the heat conduction/dissipation problem. Particularly for emerging devices based on 2D materials such as graphene, there is an opportunity to impact the device performance at the early stages of device development. We present a method that allows for the thermoreflectance signal to be detected at frequencies beyond 50 MHz, which leads to the ability to measure short-range heat transport, where most of the heat dissipation bottlenecks in small scale devices exist.