Enhanced thermal conductivity in TiC/diamond or Cr3C2/diamond particles modified Bi-In-Sn compounds

Improving thermal conductivity is a critical issue in chip integration. In this work, the thermal conductivity of Bi-In-Sn (BIS) compounds was enhanced via the introduction of TiC/diamond or Cr3C2/diamond particles. The results show that the melting point of BIS/diamond composites was close to that of BIS (similar to 60 degrees C). When the volume of diamond was the same as that of BIS, the sensible heat of diamond contributed similar to 12% to the volumetric latent heat of fusion of BIS/diamond composites. Voids/gaps existing in the interface between BIS and uncoated diamond were decreased using diamond particles coated with TiC or Cr3C2. The thermal conductivity of BIS (18 +/- 0.39 W m(-1) K-1) was each improved similar to 106% and similar to 100% by adding TiC and Cr3C2-coated diamond particles (37 +/- 1.26 W m(-1) K-1 for BIS/TiC diamond and 36 +/- 1.24 W m(-1) K-1 for BIS/Cr3C2 diamond). The effect of carbide coating thickness on the thermal conductivity of the composites was investigated. Over thick carbide coating on diamond particles would decrease the thermal conductivity of BIS/diamond composites. Simulation results indicate that the thermal conductivity of BIS/diamond composites decreased with the increasing thickness of carbide coating. Voids existing in the interface between BIS and diamond would dramatically decrease the thermal conductivity of the composites. Further, the thermal conductivity of BIS/diamond composites decreased with the increase of volume fraction of voids.