Effect of nitrogen doping on the structure of metastable /3-W on SiO2

Abstract

Metastable /3-W phase exhibits a large spin Hall effect which has attracted a great interest for spin-orbit torquebased memory applications. Here we study the growth and structure of W films prepared by magnetron sputtering under different argon and nitrogen gas mixture conditions. X-ray diffraction and sheet resistivity show that low argon with low nitrogen gas flow stabilizes the /3-W phase in thick films. High argon gas flow promotes the growth of porous /3-W films which increases the oxygen content and the resistivity of the films. It is observed that the N2 doping of the W films reduce the perpendicular magnetic anisotropy of an adjacent CoFeB layer.