Dependence of nitrogen content and deposition rate on nitrogen pressure and laser parameters in ArF excimer laser deposition of carbon nitride ®lms

The effect of N2 pressure and laser ¯uence on the chemical composition and growth rate of CNx (0:07 < x < 0:45) ®lms deposited by ArF excimer laser ablation of a graphite target in nitrogen environment is reported. Between 1 and 50 Pa the nitrogen content of the ®lms monotonously increases with increasing pressure. Films deposited at various N2 pressures differ not only in their (average) nitrogen but also in their oxygen content. The chemical composition of the ®lms deposited using pulses of ¯uences between 0.7 and 2 J cmÿ2 remains the same within experimental error, while in the 2±10 J cmÿ2 domain the nitrogen incorporation steeply increases. The growth rates vary from 0.003 to 0.56 A Ê /pulse, increasing linearly with ¯uence and decreasing with increasing pressure in the 0.7ÿ2 J cmÿ2 ¯uence domain, while followed by a supralinear dependence on ¯uence and less sensitivity to N2 pressure at higher ¯uences. Changes in ®lm porosity account for the striking features reported. # 2000 Elsevier Science B.V. All rights reserved.