Paper MN-TuP4
Nanotribological Studies of Platinum Coated Probes Sliding against Coated Silicon Wafers For Probe-based Recording Technology

Tuesday, October 16, 2007, 6:00 pm, Room 4C

Some of the new alternative information storage technologies being researched are probe-based recording techniques. In one of techniques, a phase-change medium is used and phase change is accomplished by applying either high or low magnitude of current which heats the interface at different temperatures. Tip wear at high temperature is a serious concern. For wear protection of the phase-change chalcogenide media, diamondlike carbon (DLC) film and various lubricant overcoats were deposited on the recording layer/silicon substrate. Nanotribological properties of platinum (Pt) coated probes with high electrical conductivity have been investigated in sliding against the coated media using an atomic force microscope (AFM). A silicon grating sample and SPIP software of Image Metrology were used to characterize the change in the tip shape and evaluate the tip radius. The wear tests were performed at the sliding velocity ranging from 100 µm/s to 100 mm/s. Pt-tips on the lubricant coated DLC film surfaces showed less sensitivity to the velocity and the load as compared to the unlubricated DLC film surfaces. The lubricant coatings could be used to reduce Pt-tip wear and friction between Pt-tip and DLC film surfaces. The results suggest that wear mechanism at low speed appears to be adhesive. At high speeds, the wear primarily depends on surface chemistry of the coated layers such as tribochemical oxidation.