Temperature-Dependent Thermal Boundary Conductance at Metal/Indium-Based III–V Semiconductor Interfaces

Abstract

At the microscale length and smaller, solid–solid interfaces pose a significant contribution to resistance, resulting in a build-up of energy carriers, in turn leading to extreme temperature gradients within a single electronic component. These localized temperature gradients, or “hot spots,” are known to promote degradation, thus reducing device longevity and performance. To mitigate thermal management issues, it is crucial to both measure and understand conductance at interfaces in technologically relevant thin film systems. Recent trends in photonic devices have been pushing the consumption of indium in the U.S. to grow exponentially each year. Thus, we report on the temperature-dependent thermal boundary conductances at a series of metal/In-based III–V semiconductor interfaces. These measurements were made using time-domain thermoreflectance (TDTR) from 80 to 350 K. The high-temperature thermal boundary conductance results indicate, for these interfaces, that interfacial transport is dominated by elastic transmission, despite varying levels of acoustic mismatch. There is a strong direct correlation between the interfacial bond strength, approximated by the picosecond acoustics, and the thermal boundary conductance values. Both the interfacial bond strength and the overlap in the phonon density of states (PDOS) play significant roles in the magnitude of the thermal boundary conductance values. Measurements are compared against two separate predictive models, one for a perfect interface and one which accounts for disorder, such as interfacial mixing and finite grain sizes.