Patent ID: 10115892

Abstract:
A seed layer stack with a uniform top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a smoothing layer such as Mg where the latter has a resputtering rate 2 × to 30 × that of the amorphous layer. The uppermost seed (template) layer is NiW, NiMo, or one or more of NiCr, NiFeCr, and Hf while the bottommost seed layer is Ta or TaN, for example. Accordingly, perpendicular magnetic anisotropy in an overlying magnetic layer is maintained during high temperature processing up to 400° C. and is advantageous for magnetic tunnel junctions in embedded memory devices, or read head sensors. The amorphous seed layer is SiN, TaN, or CoFeM where M may be B.