Qualitative link between work of adhesion and thermal conductance of metal/diamond interfaces

Abstract

We report Time-Domain ThermoReflectance experiments measuring the Thermal Boundary Conductance (TBC) of interfaces between diamond and metal surfaces, based on samples consisting of [111] diamond substrates with hydrogen or with sp 2 carbon surface terminations created using plasma treatments. In a concurrent theoretical study, we calculate the work of adhesion between Ni, Cu and diamond interfaces with [111] surface orientation, with or without hydrogen termination of the diamond surface, using first-principles electronic structure calculations based on density functional theory (DFT).We find a positive correlation between the calculated work of adhesion and the mea-sured conductance of these interfaces, suggesting that DFT could be used as a screening tool to identify metal/dielectric systems with high TBC We also explain the negative effect of hydrogen on the thermal conductance of metal/diamond interfaces. a) Corresponding author,

Thermal boundary conductance between refractory metal carbides and diamond

“…Using this technique on metal/diamond systems, the diamond surface chemistry was shown to have a strong impact on the TBC between diamond and metals [23][24][25]. Hydrogen-terminated diamond surfaces were found to always be detrimental to obtaining high TBC [18,24]. This was rationalized by the fact that hydrogen termination also lowers the metal/diamond work of adhesion, thereby weakening the bonds between metal and diamond [18].…”

“…Hydrogen-terminated diamond surfaces were found to always be detrimental to obtaining high TBC [18,24]. This was rationalized by the fact that hydrogen termination also lowers the metal/diamond work of adhesion, thereby weakening the bonds between metal and diamond [18]. By using an oxygen plasma treatment of the diamond surface, it was shown that both a good adhesion and a high TBC can be obtained between a metal and diamond [24,25].…”

“…The latter process has led to particularly high thermal conductivity of up to 907 Wm −1 K −1 for 100nm thick coatings, while thicker coatings reduced the beneficial effect. It is however unclear whether the conductivity improvement achieved when a carbide is present at the matrix/filler interface is due to an improved interfacial adhesion [17,18], or to the presence of a phase with phononic properties intermediate between filler and matrix [19,20], as these effects have both been shown to improve the interface conductance. A convenient method to measure the TBC at a metal/dielectric interface directly is Time-Domain ThermoReflectance [21,22] (TDTR).…”

Temperature dependence of the thermal boundary conductance in Ag–3Si/diamond composites

“…It has recently been shown that the nature and the strength of the chemical bond have a direct influence on the heat transfer coefficient [1,2]. Hence, improving the bonding between matrix and inclusion phases and therefore heat transfer across the interface may give access to an overall improved thermal conductivity of the composite.…”

Microstructural characterization and quantitative analysis of the interfacial carbides in Al(Si)/diamond composites

“…welldefined plain and large synthetic diamond monocrystal surfaces with sputtered layers of Al and other metals creating a carbide-forming interlayer. The ITC is then calculated by means of TDTR time-domain thermoreflectance experimental setup [10,11,15]. In [14] the positive influence of oxygenation on ITC was for the first time shown to be true in the low (4 K) to ambient temperature range for a Ag3Si/diamond system, fabricated under typical ''messier'' lab-scale conditions of gas pressure infiltration using synthetic diamond particles.…”