Hybrid Nanostructures Based on Aluminium Nitride and Carbon Nanotubes/ Nanowalls as Thermal Interface Materials

摘要

Carbon nanotubes (CNTs) and graphenes are nanostructured carbon materials which possess unique thermal conductivity, with a theoretical value ~ 3000 W/m. Κ for CNTs and 4000-5000 W/m. Κ for graphene layer sheets [1]. Therefore, they can be exploited for use as thermal interface materials (TIMs) to address thermal management issue in microelectronics. Carbon nanowalls (CNWs) are another emerging carbon nanomaterials, they consist of stacked graphene nanodomains, assembled in sheets with high aspect ratio, standing vertically on the substrate [2]. Thus, they could also be used as TIMs. In this contribution, we present the thermal conductivity of CNWs and vertically aligned CNTs films with controlled lengths and site density. In a first stage we show that the effective thermal conductivity of CNWs films is similar or even higher than those of CNTs experimental values reported previously (15-20 W/m. K) [3]. In a second stage, the vertically aligned CNTs arrays and CNWs were embedded in dielectric aluminium nitrides (A1N) matrix via magnetron sputtering technique, in order to enhance their thermal conductivity. Such hybrid nanostructures which are composed of A1N and CNTs or CNWs can be used as passivation layer while also acting as a. heat spreader in high electron mobility transistors devices. The structural, compositional, and interfacial characterizations of these nanostructures at each processing stage were carried out using advanced characterization tools such as SEM, TEM, XRD, and Raman Spectroscopy. The results from thermal characterization of such hybrid nanostructures (CNTs/AIN and CNWs/AIN) will also be presented and discussed.