AbstractRecent studies indicate that reactively sputtered FeCrTaN nanocrystalline thin films have many of the properties [large magnetization (4πMs), anisotropy (Han), and resistivity (ρ)] required for application in high Q (>1000), magnetically tunable devices operating in the VHF/UHF (∼50 MHz to 500 MHz) frequency range. These films had thickness (d) of ∼0.1 -µm, but film thickness of ∼1-µm may be required for many devices. Although most previous research has shown that the magnetic properties of sputtered films are significantly deteriorated when d∼1-µm, there are recent reports that those of reactively sputtered nanocrystalline films of similar alloys (FeTaN, CoAl/SiO) are independent of thickness to d≈1-2-µm. Accordingly, this work investigated the possibility of reactively sputtering FeCrTa alloys in O/N gas mixtures to obtain films with device quality properties, that are independent of thickness to 1-2µm. The correlations between their magnetic and electrical properties, and their nano-heterogeneous microstructure, were studied to determine optimum reactive gas mixtures and sputtering parameters. Cross-section TEM studies were conducted to investigate the origins of the thickness independent properties, and the unexpected increases in anisotropy.
Effect of porous barriers on the molecular compositions of reactive gas mixtures
