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US 12,745,569 B2Granted
Magnetic tunnel junction stack and method for manufacturing the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsNuo Xu, Po-Sheng Lu, Zhi-Ren Xiao, Zhiqiang Wu
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Abstract
A magnetic tunnel junction (MTJ) stack includes a reference layer, a tunnel barrier layer, a free layer, and a superparamagnetic layer. The reference layer has a fixed magnetization direction. The tunnel barrier layer is disposed on the reference layer, and includes an insulating material. The free layer has a changeable magnetization direction, and is disposed on the tunnel barrier layer opposite to the reference layer. The superparamagnetic layer is disposed on the free layer opposite to the tunnel barrier layer. Methods for manufacturing the MTJ stack are also disclosed.
Claims20
A method for manufacturing a MTJ stack, comprising:
- forming a stacking portion which includes
- a reference layer with a fixed magnetization direction,
- a tunnel barrier layer formed on the reference layer, the tunnel barrier layer including an insulating material,
- a free layer formed on the tunnel barrier layer opposite to the reference layer, the free layer having a changeable magnetization direction, and
- a precursor stack formed on the free layer, the precursor stack including
- at least one repeating unit which includes a non-magnetic layer and a magnetic layer, the non-magnetic layer being disposed between the magnetic layer and the free layer, and
- an additional non-magnetic layer formed on the at least one repeating unit opposite to the free layer;
- and
- after forming the stacking portion, performing a thermal treatment such that the at least one repeating unit and the additional non-magnetic layer are inter-diffused with each other so as to form a superparamagnetic layer on the free layer,
- wherein a material of the superparamagnetic layer is represented by AxB(1-x), where
- A is tungsten (W), silicon (Si), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), lead (Pb), or combinations thereof,
- B is cobalt (Co), iron (Fe), nickel (Ni), or alloys thereof, and
- x is larger than zero and less than 1.
10 more elements
A method for manufacturing a MTJ stack, comprising:
- forming a reference layer with a fixed magnetization direction;
- forming a tunnel barrier layer on the reference layer, the tunnel barrier layer including a first insulating material;
- forming a free layer on the tunnel barrier layer opposite to the reference layer, the free layer having a changeable magnetization direction;
- forming a precursor stack which includes
- at least one repeating unit which includes a non-magnetic layer and a magnetic layer, the non-magnetic layer being disposed between the magnetic layer and the free layer, and
- an additional non-magnetic layer on the at least one repeating unit opposite to the free layer;
- and
- performing a thermal treatment such that the at least one repeating unit and the additional non-magnetic layer are inter-diffused with each other so as to form a superparamagnetic layer,
- wherein the superparamagnetic layer includes sub-layers each of which has a material represented by AxB(1-x), where
- A is tungsten (W), silicon (Si), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), lead (Pb), or combinations thereof,
- B is cobalt (Co), iron (Fe), nickel (Ni), or alloys thereof, and
- x is larger than zero and less than 1, and
- wherein x in one of the sub-layers is different from x in another one of the sub-layers.
10 more elements
A method for manufacturing a MTJ stack, comprising:
- forming a reference layer with a fixed magnetization direction;
- forming a tunnel barrier layer on the reference layer, the tunnel barrier layer including a first insulating material;
- forming a free layer on the tunnel barrier layer opposite to the reference layer, the free layer having a changeable magnetization direction;
- forming a capping layer on the free layer opposite to the tunnel barrier layer, the capping layer including hafnium oxide, zirconia oxide, tantalum oxide, or tungsten oxide;
- and
- forming a precursor stack on the capping layer opposite to the free layer, the precursor stack including
- at least one repeating unit which includes a non-magnetic layer and a magnetic layer, the non-magnetic layer being disposed between the magnetic layer and the free layer, and
- an additional non-magnetic layer formed on the at least one repeating unit opposite to the free layer;
- performing a thermal treatment such that the at least one repeating unit and the additional non-magnetic layer are inter-diffused with each other so as to form a superparamagnetic layer on the free layer opposite to the tunnel barrier layer, the superparamagnetic layer having a magnetization direction different from that of the free layer, the capping layer being disposed between and interfacing the free layer and the superparamagnetic layer.
6 more elements
Dependencies are inferred from the claim text.