Comparison and semiconductor properties of nitrogen doped carbon thin films grown by different techniques F. Alibart a , O. Durand Drouhin a , M. Benlahsen a, *, S. Muhl b , S. Elizabeth Rodil b , E. Camps c , L. Escobar-Alarcon c a Laboratoire e Physique de la Matie `re Condense ´e, 33 rue Saint Leu, 80000 Amiens, France b Instituo de Investigationes en Materials, Universidad National Autonomia de Mexico, Mexico, D.F. 04510, Mexico c Instituo National de Investigationes Nucleares, Apdo. Postal 18-1027, Mexico, D.F. 11801, Mexico 1. Introduction Amorphous carbon nitride thin films (a-CN x ) have been intensively studied during the last twenty years due to their promising mechanical properties predicted from the theoretical studies of the b-C 3 N 4 crystalline structures [1]. The high hardness and strong resistance to wear, comparable to those of diamond, would make this material valuable and much wanted material for industrial applications such as the coating of mechanical parts. Various techniques have been used for the preparation of the carbon nitride films under a wide range of deposition parameters [2–5]. Although, most of the synthesised materials have nitrogen content lower than the stoichiometric proportion for the C 3 N 4 (57 at.%), the new amorphous a-CN x phases are of both scientific and practical interest [2–5], in particular in the field of optoelectronic devices, such as, gate insulator for OTFT, electron injection layer in OLEDs, or active layer in TFTs but the industrial utilisation of such films is still not of actuality [6–10]. From the numerous studies conducted on the a-CN x , it has been clearly shown that the method of nitrogen incorporation (i.e. deposition conditions and system) determines both the nitrogen content and the prevalent C–N bonding configuration (sp 1 , sp 2 and sp 3 ) in the deposited film, and therefore their physical properties. It has been reported that N atoms and CN radicals are the main precursors for the deposition of amorphous a-CN x films in intense nitrogen discharges [5,11–12]. According to the literature, the properties of amorphous carbon (a-C) films are governed mainly by the nitrogen content, the substrate temperature and the energy of carbon species during deposition [2,11]. The aim of this study was to investigate the effect of nitrogen incorporation on the electrical and optical properties of the films comparing three different deposition techniques. The used techniques were Direct Current (DC) magnetron sputtering, DC pulsed magnetron sputtering and RF magnetron sputtering. A common feature of all these techniques is that the carbon species arriving at the substrate have a definite energy (or energy range) which can be varied and the deposited Applied Surface Science 254 (2008) 5564–5568 ARTICLE INFO Article history: Received 16 October 2007 Received in revised form 28 February 2008 Accepted 29 February 2008 Available online 6 March 2008 PACS: 78.40.Fy 81.05.Hd 81.15.Fg Keywords: Carbon nitride DC sputtering Radio frequency magnetron sputtering Pulsed laser deposition ABSTRACT Amorphous carbon nitride (a-CN x ) thin films have been synthesised by three different deposition techniques in an Ar/N 2 gas mixture and have been deposited by varying the percentage of nitrogen gas in the mixture (i.e. the N 2 /Ar + N 2 ratio) from 0 to 10%. The variation of the electrical conductivity and the gap values of the deposited films versus the N 2 /Ar + N 2 ratio were investigated in relation with their local microstructure. Film composition was analysed using Raman spectroscopy and optical transmission experiments. The observed variation of electrical conductivity and optical properties are attributed to the changes in the atomic bonding structures, which were induced by N incorporation, increasing both the sp 2 carbon content and their relative disorder. The low N content samples seem to be an interesting material to produce films with interesting properties for optoelectronic applications considering the facility to control the gas composition as a key parameter. ß 2008 Elsevier B.V. All rights reserved. * Corresponding author. E-mail address: mohamed.benlahsen@sc.u-picardie.fr (M. Benlahsen). Contents lists available at ScienceDirect Applied Surface Science journal homepage: www.elsevier.com/locate/apsusc 0169-4332/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2008.02.108