Tribological and surface characterisation in UHV of amorphous CNx films

The performance of many industrial tools and electronic components strongly depends on the tribological properties of the contact surfaces in relative motion. The role of the thin film coating for this kind of applications is to act as a solid lubricant between the sliding surfaces decreasing the friction coefficient and wear. The investigation of the processes appearing in the interface necessarily requires the employment of surface-sensitive techniques such as XPS and AES to determine its nature and origin. The development of a pin-on-flat tribometer directly installed in the UHV analytical chamber coupled with surface analysis methods is presented here for the study of tribological behaviour of amorphous carbon nitride (CNx) films. The good spatial resolution of XPS (about 100 mum) and AES (about 0.5 mum) allows in situ surface analysis inside and outside of the wear scars on flat and pin. We report the application of the AES/XPS analytical UHV tribometer for the study of the friction mechanisms of CNx films tested in air (analysis ex situ) and UHV conditions (analysis in situ). Owing to AES elemental distribution and XPS, the surface related phenomena connected with the tribological behaviour have been identified and discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.