John C. Duda’s paper published in Applied Physics Letters: “Systematically controlling Kaptiza conductance via chemical etching”

Our paper, ” Systematically controlling Kaptiza conductance via chemical etching,” was recently published in Applied Physics Letters (Appl. Phys. Lett. 100, 111602 (2012)).  In this work, we investigated the relationship between surface roughness and Kaptiza conductance at an Al/Si interface and showed that with low cost, chemical etching, precise control over this thermal conductance can be realized.  The temperature dependence of the Kaptiza conductance lends insight into the various phonon frequencies that are contributed to interfacial heat flow.   We see similar temperature trends as we previously observed with quantum dot patterning, indicting that the phonon scattering mechanisms at rough interfaces are based on the geometry and degree of roughness, not the means of roughening.


We measure the thermal interface conductance between thin aluminum films and silicon substrates via time-domain thermoreflectance from 100 to 300 K. The substrates are chemically etched prior to aluminum deposition, thereby offering a means of controlling interface roughness. We find that conductance can be systematically varied by manipulating roughness. In addition, transmission electron microscopy confirms the presence of a conformal oxide for all roughnesses, which is then taken into account via a thermal resistor network. This etching process provides a robust technique for tuning the efficiency of thermal transport while alleviating the need for laborious materials growth and/or processing.

This work was funded by NSF (CBET Award #1134311)

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