Thermal interfacial transport in the presence of ballistic heat modes

Bjorn Vermeersch, Birck Nanotechnology Center, Purdue University
Amr M.S. Mohammed, Purdue University, Birck Nanotechnology Center
Gilles Pernot, Universite Bordeaux I
Yee Rui Koh, Birck Nanotechnology Center, Purdue University
Ali Shakouri, University of California - Santa Cruz; Birck Nanotechnology Center, Purdue University

Abstract

Thermal interface (Kapitza) resistance expresses how hard it is for heat to flow across material junctions inside multilayer structures. This quantity plays a crucial role in the thermal performance of nanoscale devices but is still poorly understood. Here we show that conventional Fourier-based metrology overestimates metal/semiconductor resistances by up to threefold due to misinterpretation of ballistic heat flow modes. We achieve improved identification and a different physical insight with a truncated Levy formalism. This approach properly distinguishes interfacial dynamics from nearby quasiballistic heat flow suppression in the semiconductor. Unlike conventionally extracted values, interface resistances obtained with our new approach are independent of laser modulation frequency, as physically appropriate, and much more closely approach theoretical predictions.

Discipline(s)

Nanoscience and Nanotechnology