B content dependence on anisotropy field of CoFeB thin film for GHz frequency use

In this study, in order to obtain the larger anisotropy field, B was added to the CoFe phase (Co/sub 35/Fe/sub 65/, Co/sub 25/Fe/sub 75/, and Co/sub 15/Fe/sub 85/ with high saturation magnetization more than 20 kG) by using synchronous triple-RF magnetron sputtering. Dependence of B content on anisotropy field and crystal structure of CoFeB thin films was investigated. Very large anisotropy field of 500-700 Oe for obtaining higher FMR frequency was obtained. The result shows a good potential for obtaining magnetic cores driven at higher frequencies of several GHz.