Controlled Growth of Co Nanofilms on Si(100) by Ion-Beam puttering
Résumé
The effect of process conditions on the properties of cobalt films grown on silicon by ion-beam sputtering is analyzed from the nucleation stage to film thicknesses corresponding to the properties of bulk material. The argon ion energy is shown to play a central role in determining the sputtering process. Sputtering a cobalt target with argon ions less than 0.8 keV in energy produces granular layers. The cobalt layers grown at argon ion energies above 1.2 keV are continuous even in the nucleation stage. The layers 1.2 to 2 nm in thickness have high resistivity and are comparable in magnetic properties to bulk material. The high-energy component of the total flux of cobalt atoms ejected from the target plays an important role in the initial stages of deposition, especially at argon ion energies from 1.2 to 2.2 keV. In the nucleation stage, the energy deposited by cobalt atoms in the silicon substrate facilitates the formation of a continuous layer in the initial stage of the process.