Electrical and thermal characterization of carbon nanotube films

The remarkable electrical and thermal properties of carbon nanotubes (CNTs) make them attractive for microelectronics applications and, in particular, for interconnects. A multilayer device was designed in order to measure electrical and thermal properties of CNT films. This device is composed of an iron catalyst thin film deposited by pulsed laser ablation upon which a dense multi-walled carbon nanotube (MWCNT) film was grown by radio frequency plasma enhanced chemical vapor deposition. Finally a thin metallic layer was deposited over all by physical vapor deposition. Scanning electron microscopy images were intensively used to check the length (several tens of micrometers) and diameter (10 to 30 nm) of the nanotubes and to adjust the different steps of the process to get the desired film morphology (dense and vertically aligned). The CNT structure was investigated by high-resolution transmission electron microscopy and Raman spectrometry. The MWCNT carpet showed an ohmic behavior during current-voltage characterization tests by the four-probe method. Its thermal properties were determined by time-resolved infrared pyrometry tests and its apparent thermal conductivity was found to be between 180 and 220 Wm(-1) K-1. The measurements were found to fit well with a 1D thermal transfer model. The electrical and thermal properties of the device disclosed that CNTs films can be considered heat sinks. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3607317]