ELSEVIER ThinSolid Films 290-29l (1996) 103-106 Investigation of carbon nitride films by cathodic arc evaporation M. Chhowalla ~, I. Alexandrou a C. Kiely a.~, G.A.J. Amaratunga ~, R Aharonov 1, R.F. Fontana b " University t~fl.iverp~ol, Dept ~fElet'lrical Eflgtae~ rillg a~ldEle.¢lrtmics, L~e~'inlol L693BX, Ulf, h MMti.Arc Inc., 200 Rollmlhil! drive, Nockaway, NJ 07866, USA Abstract Presently there is great interestin deposition of Ihe/3.phase C~N4 hecauseits predictedhardness and randall exceed thoseof diamond,The u~ of energetic particle beam methodshave showT~ promise in terms of nitrogen incorporation, Energetic and highly ionized beams from cathodic arcs have also provento be effective in deposilionof tctrahcdral amorphous carbon (ta-C). In this paper we reporton C-N films deposited using a earbnnsrc in nitrogenatmosphere.Filmswith nitrogenconcemmdon rangingfrom 17-32% were deposited as a function of nitrogen pressureand subslratetemperature,CN~ filmsdeposited above roam temperatureand I reTort ~0,013 Pa) of N~ were found to have low stress, indicating the presenceof mostlysp 2bonding, tfcyword.r: Cathodic arcs;Carbon nilfide trims 1, Introduction The deposition of ~-C.aN,~ has recently taken on interest duc to its extreme predicted hardness and moduli [ 1 ], How- ever, the deposition of the/:I-C~N~phase has been limited to small cryslalline areas in an amorphous C-N matrix which makes mechanical characterization of its properties di flicult, Although the deposition of C-N films has been geared towards obtaining the ~8-C.~N., phase, new types of C-N mate- rials with interesting mechanical properties have been found from this research [2], The limited success in depositing Ihe /3-C~N4 phase has been achieved by using carbon and nitro- gen ion beams [3,4], 1his is attributed to the presence ofN ~ species which are more reactive making the iacopnration of close to 57% nitrogen required for/3-C3N4more likely. Since the nitrogen content in the film will be related to the partial pressure and substrata temperature during growth, numerous studies have investigated the C-N properties as a function of these paramelers [ 5,6]. Since the deposition of the crystalline phase has been lim- ited, the characterization ofthe C-N films has primarily con- centrated oR investigating the bonding structure of the films using techniques such as x-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FFIR), In conjunction with the information obtained on the bonding I University of Li,,,erpo~l,I)ept,~f MalerialsScience, Liverpool L69 3BX. UK~ using FTIR, high resolution transmission eleetron micros- copy (HREM) has also been used to study the microstructurc of the films [2,51, In this paper we report on carbon nitride films deposited using a cathodic carbon are in a nitrogen ambient. The cathodic arc may be efficient in providing N ÷ species due to the high plasma density near the arc spot, In particular, prop- erties such as compressive stress, hardness, bonding, refrac- tive index and nitrogen concentration of the films are invcstigaled as a function of the nitrogen pressure, (PN~) and substrata temperatune ( ~ ) . The deposition rate was tbund to increase as a fuction of the P~2 and T, while the compressive stress in the film was found to decrease with substrata tem- perature and nitrogen partial pressure. The FTIR spectra showed a feature at 2200 cm- l indicating the presence of C- N linear sp sites, The 2200 em - k feature was more prominent for nitrogen partial pressures greate~ than 6mTorr (0.780 Pa), The resislivity measurements showed n-type doping behavior ofla-C with nitrogen pressure as previously observed I71. 2, Experimental details The CN, films were deposited using a Multi-Are Inc, cathodic arc system where a 99,999% purity high density graphite cathode is the plasma source. The are en the cathode is struck by contacting it with a retractable earthed graphite anode of similar purity. The nitrogen gas (99,9995% in 0040-6090/%t$15.00 @ 1996 Published hy Elsevier ScienceS.A.All rights n~servcd PI! 0040-6090( 96)09067-0