Large-scale production and metrology of vertically aligned carbon nanotube films

The authors have produced carbon nanotube (CNT) films on a large scale in a commercial chemical vapor deposition (CVD) reactor. The reactor (built by Tystar, Inc) is the first of its kind and is capable of handling up to 50 150mm wafers simultaneously with industry standard process control. Electron microscopy reveals that the CNT films consist of densely packed and vertically aligned multiwalled CNTs. A variety of catalysts and reaction conditions were systematically tested. Both Fe films and Cr 15Ni 15Fe film stacks have been found favorable for the growth of aligned CNT films. While electron microscopy provides invaluable information, it is qualitative and unsuitable for process optimization and industrial quality control. A quantitative metrology standard is required for these purposes, but has to date not been explicitly defined. They report on their initial developments toward this metrology standard, considering such factors as film thickness (or CNT length), CNT wall number and diameter, amorphous carbon content, and uniformity. Various measurement techniques have been investigated and are discussed. The developed metrology will facilitate quality control and process optimization necessary for industry applications of CNT films.Peer reviewed: YesNRC publication: Ye