AFM Characterization of insulating CaF2 Layers on a Si Wafer

Atomic Force Microscopy (AFM) has been used in order to characterize the surface topography of insulating CaF2 layers. CaF2 thin films were deposited on Si (111) substrates by means of thermal evaporation. The Si substrates were chemically cleaned prior to insertion into the system. The final volatile oxide was desorbed in situ by heating to 850°C. CaF2 was evaporated from a Knudsen –type cell by used of a graphite crucible, while the growth temperature was held at 650 °C. Electrical properties are measured by use of a special MIS structure.