The thermal resistivity of diamond heat-sink bond materials

Abstract

The thermal resistivity of diamond heat-sink bonds in the form of sputtered titanium and gold films has been measured from 1.2 to 300K. The addition of epitaxial nickel to the diamond lattice improved the thermal conductivity of the bond by approximately ²/₃ at room temperature. The standard metallic bond was found to be equivalent to approximately 1.2 mm of type IIa diamond at room temperature. At low temperatures the standard bond resistivity was given by R=1.78*10^-3T^-2.3K m² W^-1, whereas phonon mismatch theory predicts R=7.35*10^-3T^-3K m² W^-1. These results suggest that electron heat transfer across the bond is very important.