Quantifying the Influence of Surface Roughness on Conductive Heat Transfer at Liquid/Solid Interfaces

Rapid developments in extreme ultraviolet lithography are soon expected to produce integrated circuit components with feature sizes of about 10 nm. Heat transfer at this scale is known to differ substantially from Fourier’s law. Interfacial or so-called Kapitza resistance, which tends to increase with diminishing system size, hinders effective heat evacuation thereby undermining device reliability. Although numerous experiments and simulations over the past few decades have elicited trends in the Kapitza resistance which correlate with system size and surface roughness, good quantitative understanding for atomistically rough interfaces is still lacking. In this talk, we discuss some of the effects on Kapitza resistance induced by surface roughness at liquid/solid interfaces as investigated by non-equilibrium molecular dynamics simulations using realistic solid walls modeled by an interacting 12-6 Lennard-Jones potential. Detailed comparison between atomistically smooth and rough interfaces contrasting such behavior as the vibrational density of states will be examined in an effort to interrelate the phonon spectrum and phonon modes transmitted across the interface with various quantitative measures characterizing interfacial roughness.