Targeting mass-selected cluster ions for the deposition of advanced carbonaceous materials using an inductively coupled plasma

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Study has been initiated of the deposition of thin films using cluster ions in differing abundances generated in a pulsed inductively coupled plasma. A pulse unit controlling the ''on'' and ''off'' timing ratio of a 13.56 MHz rf power supply is used to alter systematically the composition of the contents of the plasma. Adamantane ͑C 10 H 16 ͒ vapor, in argon or nitrogen, was selected as precursor for the deposition of C x H y or C x N y H z thin films using this pulsed source. The effect of varying the relative abundances of the cluster ions present in the resultant plasmas on the films produced, by changing driving power on/off ratio, is investigated. The mass-energy diagnostic data recorded under 50/150 and 150/50 s on/off pulse sequences showed that fragmentation of C 10 H 16 is a function of the switching ratio selected, i.e., clusters of different sizes and abundances are thus produced. Langmuir probe data also suggest that the electrical characteristics of the plasma generated under these regimes can be monitored. Postdeposition x-ray photoelectron spectroscopy ͑XPS͒ analysis of specimen films deposited under the same on/off regimes, within a 200 s cycle, indicate clear differences are present in these films in terms of the atomic concentration, the C 1s envelope bandwidths, and profiles. Contact angle measurements and optical data performed were found to reflect the variations in the differently deposited films already indicated in the XPS data. For example, specimens deposited under a 50/150 on/off ratio show a high contact angle ͑low surface energy͒ and lower refractive index, whereas those deposited under a 150/50 ratio exhibit a low contact angle ͑high surface energy͒. Films prepared using the same precursor streams but with the further on/off ratios, 20/180, 100/100, and 20/180 s, were also considered. Postdeposition analyses confirmed the same tends in the fragmentation behavior of C 10 H 16 . Finally, the significance of such a cluster ions selection technique is discussed.