Enhanced interfacial transport using carbon nanotube arrays

Summary form only given. A major challenge for achieving reliable, high-performance semiconductor devices and circuits is to reduce the thermal and electrical interfacial and constriction resistances. Reduction of thermal contact resistance at solid interfaces enables larger temperature differences between the convective surfaces and cooling media. On the other hand, the heat generation in most devices is not distributed uniformly; therefore, spreading the heat from the hottest spots effectively and maintaining an acceptable temperature at these spots are also critical to thermal reliability (June and Sikka, 2002). Similar issues involving current crowding exist for electrical transport. Recently, significant attention has focused on using highly thermal conductive carbon nanotubes (CNTs) for thermal contact conductance enhancement. Among the several reported works, Xu and Fisher (2005) have reported interfacial resistance values of 19.8mm²K/W and 5.2mm²K/W under moderate pressures for copper-silicon interfaces with dry and composite CNT arrays, respectively. Ngo et al. (2004) used copper as a gap filler to enhance the stability and thermal conductance of carbon nanofiber (CNF) arrays. They reported a resistance of 25mm²K/W at 60psi for Cu-Si interfaces. This presentation provides an overview of results to date on the thermal and electrical resistances of interfaces that contain carbon nanotubes. Modeling techniques are also discussed, and challenges and opportunities for further research are presented.