Surface chemistry and properties of carbon overcoats for magnetic data storage

The surface chemistry and properties of amorphous carbon films used in magnetic hard disk data storage media were studied in this thesis. This thesis includes two projects: vapor phase lubrication of hydrogenated amorphous carbon (a-CHx) films and thermal stability analysis of fluorinated amorphous carbon (a-CFx) films.;The surface heterogeneity of a-CHx film was probed through the use of temperature programmed desorption of small fluorocarbon models of Fomblin Zdol lubricants. Surface oxidation by exposing a-CHx film to air or O2 strengthens the hydrogen bond between the hydroxyl endgroups of Fomblin Zdol lubricant molecules and the a-CHx film surfaces. Thus the interaction between Fomblin Zdol lubricant molecules and the a-CHx film surfaces can be tailored by controlled oxidation of a-CHx film surfaces prior to vapor phase lubrication.;Methods for the preparation of high thermal stability a-CFx films were evaluated by our analysis of a-CFx film thermal stability. a-CFx films having high concentrations of CF3 and CF 2 have better thermal stability than those with high fractions of CF. Oxidation, however, jeopardizes the thermal stability of a-CFx films and thus should be avoided in application.;The oxidation of a-CHx films and a-CFx films and its kinetics were studied by analysis of the fresh carbon film surfaces before and after controlled oxidized. The most surprising observation has been that the exposure of a-CHx films and a-CFx films to low pressures (<10-3 Torr) of O2 or air leads to a higher level of oxidation than exposure to high pressures (100--1000 Torr) of O2 or air. It may be that this decrease in apparent oxidation during the exposure to high pressures of O2 or air is due to complete oxidation of surface carbon to CO or CO2 which desorbs from the surface ("ablation"). In essence this changes the surface composition during the oxidation process.