In English

Vertically aligned carbon nanofiber synthesis on top of TiN films for NEMS devices

María Elena López Damián
Göteborg : Chalmers tekniska högskola, 2011. 42 s.
[Examensarbete på avancerad nivå]

Plasma enhanced chemical vapour deposition is used for the synthesis of vertically aligned carbon nanofibers from Ni catalyst particles deposited by hole mask colloidal lithography on top of TiN. The TiN underlayer is reactively sputtered in a reliable and repeatable manner. TiN has been selected for its CMOS compatibility and good performance as a diffusion barrier having in mind the aim of using the carbon nanofibers for nanoelectromechanical devices (NEMS). The optimal growth conditions for the carbon nanofibers are estimated from annealing, growth temperature, gas ratio, power and pressure parameter study. The characterization of the as deposited carbon nanofibers is performed by scanning and transmission electron microscopy techniques. A growth mechanism is proposed where a carbon deposit free catalyst surface sustained during the whole synthesis results in a carbon diffusion limited growth. If the balance between the carbon bearing species and the etching agents is distorted in favor of carbon formation the growth will shift to a carbon supply-limited process instead. Transitions between aligned tip type and unaligned base type fibers are explained in terms of the dominant process at the initial phase of the growth. The growth mode will be defined by the first graphene layers site of formation being either the catalyst or the catalyst-substrate interface.

Nyckelord: Vertically aligned carbon nanofiber, VACNF, TiN, PECVD synthesis, Growth mechanism



Publikationen registrerades 2011-12-20. Den ändrades senast 2013-04-04

CPL ID: 150511

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