Nanometer scaled magnetic tunnel junctions fabricated by a substrate biased plasma etching technique

SiO/sub 2//Ta(50 /spl Aring/)/Ni/sub 81/Fe/sub 19/(60 /spl Aring/)/Fe/sub 50/Mn/sub 50/(80 /spl Aring/)/FM/sub BOTTOM/(40 /spl Aring/)/Al/sub 2/O/sub 3/(12-16 /spl Aring/)/FM/sub TOP/(100 /spl Aring/)/Ta(20 /spl Aring/) are prepared on a thermally oxidized Si(100) substrate. FM layer used is Ni/sub 81/Fe/sub 19/ or Co/sub 84/Fe/sub 16/. The effect of substrate-biased plasma etching process on magnetotransport properties in magnetic tunnel junctions compared to that of the device prepared by a conventional way is investigated. Several properties such as TMR ratio and junction resistance, magnetization switching behavior of the MTJs are also investigated.