Improved magnetic tunnel junction with amorphous seed layer, surface treatment,and high-polarization magnetic materials

Dependence of magnetic tunnel junction (MTJ) properties on seed layer, surface treatment and magnetic materials was investigated to improve TMR ratio. Roughness of tunnel oxide layer generated from seed layer roughness reduces TMR ratio as well as RA product owing to locally reduced oxide layer thickness. Crystallinity of seed layer is found to be important to enhance TMR ratio. Surface treatment with ion beam etching on a pinned layer improves tunnel oxide uniformity providing higher TMR ratio. Also, highly polarized magnetic material increases TMR ratio but the effect of surface treatment is quite different depending on pinned layer material.