Structure and composition of carbon-nitride films grown by sub-ps PLD

CNx (0.01 < x < 0.20) films have been deposited by ablating a graphite target in N-2 atmosphere with a hybrid dye/excimer laser system delivering pulses of 500 fs duration at 248 run. Changes in surface composition and morphology of the as grown films, as a function of N-2 pressure (between 0.3 and 60 Pa), laser pulse energy (maximum 10 mJ), and spot area are reported, by means of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. In the pressure domain investigated, the nitrogen content increases as a power function. While both pulse energy and spot area influence the chemical composition of the films, the same fluence achieved by using different spot sizes results in films of different N content. Deposition of micrometer sized particulates is apparently suppressed, while sub-micron features of typically circular shape are present over the smooth film surface. (C) 2002 Elsevier Science B.V All rights reserved.