Surface Science Letters Arrhenius-type temperature dependence of the chemical desorption processes active during deposition of fullerene-like carbon nitride thin films J. Neidhardt * , H. Ho¨ gberg, L. Hultman Thin Film Physics Division, Department of Physics, IFM, Linko¨ ping University, S-58183 Linko¨ ping, Sweden Received 2 June 2004; accepted for publication 19 July 2004 Available online 4 August 2004 Abstract The chemical desorption of carbon and nitrogen-containing species from the growth surface was investigated for the deposition of fullerene-like carbon nitride (FL CN x ) thin solid films by reactive magnetron sputtering of a carbon target in a N 2 -containing atmosphere. The desorption of mainly C 2 N 2 was suppressed by decreasing the substrate temperature for various N 2 fractions in the discharge stepwise from 873 K down to cryogenic temperatures of 153 K. This approach enabled us to quantify the film-forming flux by determining the carbon and nitrogen incorporation rates by elastic recoil detection. The incorporation of both, carbon and nitrogen, was found to increase substantially at lower substrate tem- peratures, whereas this effect is most pronounced for the higher N 2 fractions. In turn, a modified Arrhenius-type rate equation was applied to extrapolate the total flux of the elements as well as their respective activation energies of desorption for the series at higher N 2 fractions. The reasonable fit indicates that the desorption process is mainly deter- mined by the surface diffusion rate of adsorbed C x N y species as well as their structure and total number. The extra- polated fluxes of carbon and nitrogen atoms arriving as preformed species at the growth surface scaled strongly with the availability of N 2 in the discharge, while the obtained activation energies of 0.05–0.17 eV point towards a sat- uration of the process at elevated temperatures. Furthermore, the constant C/N ratio found in the film-forming flux leads to the notion that most of the nitrogen incorporated originates from preformed species instead of N atoms or ions. The FL structure evolution has to be seen as a sensitive interplay between the type and magnitude of preformed C x N y species in the deposition flux and the selectiveness of the preferential etching by means of the chemical desorption. Ó 2004 Elsevier B.V. All rights reserved. Keywords: Carbon; Nitrides; Nitrogen molecule; Growth; Sputter deposition; Thermal desorption 0039-6028/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.susc.2004.07.025 * Corresponding author. Tel.: +46 13 28 1232; fax: +46 13 28 8918. E-mail address: jorne@ifm.liu.se (J. Neidhardt). Surface Science 569 (2004) L289–L295 www.elsevier.com/locate/susc