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...

2007-04-24

2007-04-24

Ho, Tu-Tu (Department: 2818)

Active solid-state devices (e.g., transistors, solid-state diode

Responsive to non-electrical signal

Magnetic field

C257S295000, C257SE27006

Reexamination Certificate

active

11080860

ABSTRACT:
A high performance MTJ in an MRAM array is disclosed in which the bottom conductor has an amorphous Ta capping layer. A key feature is a surfactant layer comprised of oxygen that is formed on the Ta surface. The resulting smooth and flat Ta capping layer 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. The MTJ configuraton is extendable to a 0.2×0.4 micron MTJ bit size.

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