Structure and method to fabricate high performance MTJ...

Details Structure and method to fabricate high performance MTJ... Structure and method to fabricate high performance MTJ...

2007-05-01

2007-05-01

Le, Thao P. (Department: 2818)

Semiconductor device manufacturing: process

Having magnetic or ferroelectric component

C365S158000, C365S185190

Reexamination Certificate

active

11080868

ABSTRACT:
A method of forming a high performance MTJ in an MRAM array is disclosed. A Ta/Ru capping layer in a bottom conductor is sputter etched to remove the Ru layer and form an amorphous Ta capping layer. A key feature is a subsequent surface treatment of the Ta capping layer in a transient vacuum chamber where a self-annealing occurs and a surfactant layer is formed on the Ta surface. The resulting smooth and flat Ta surface promotes a smooth and flat surface in the MTJ layers which are subsequently formed on the surfactant layer. For a 0.3×0.6 micron MTJ bit size, a 35 to 40 Angstrom thick NiFe(18%) free layer, an AlOx barrier layer generated from a ROX oxidation of an 9 to 10 Angstrom thick Al layer, and a Ru/Ta/Ru capping layer are employed to give a dR/R of >40% and an RA of about 4000 ohm-μm2.

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