Magnetic tunnel junction device and method
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJui-Fen Chien, Wei-Gang Chiu, Tsann Lin
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Abstract
In an embodiment, a device includes: a magnetoresistive random access memory cell including: a bottom electrode; a reference layer over the bottom electrode; a tunnel barrier layer over the reference layer, the tunnel barrier layer including a first composition of magnesium and oxygen; a free layer over the tunnel barrier layer, the free layer having a lesser coercivity than the reference layer; a cap layer over the free layer, the cap layer including a second composition of magnesium and oxygen, the second composition of magnesium and oxygen having a greater atomic concentration of oxygen and a lesser atomic concentration of magnesium than the first composition of magnesium and oxygen; and a top electrode over the cap layer.
Claims20
A method comprising:
- forming a bottom electrode layer over a substrate;
- forming a ground layer over the bottom electrode layer;
- forming a seed layer over the ground layer;
- forming reference layers over the seed layer;
- forming a tunnel barrier layer over the reference layers by sputtering magnesium oxide with radio frequency (RF) sputtering;
- forming free layers over the tunnel barrier layer;
- forming a cap layer over the free layers by repeatedly depositing and oxidizing magnesium;
- forming a top electrode layer over the cap layer, the cap layer comprising magnesium oxide extending continuously between the top electrode layer and the free layers;
- and
- patterning the top electrode layer, the cap layer, the free layers, the tunnel barrier layer, the reference layers, the seed layer, the ground layer, and the bottom electrode layer to form a magnetoresistive random access memory cell.
A method comprising:
- depositing a reference layer over a bottom electrode layer;
- depositing a tunnel barrier layer over the reference layer by sputtering magnesium oxide with radio frequency (RF) sputtering;
- depositing a free layer over the tunnel barrier layer;
- forming a cap layer over the free layer by repeatedly depositing and oxidizing magnesium, the cap layer comprising magnesium oxide directly contacting the free layer;
- depositing a top electrode layer over the cap layer;
- and
- patterning the top electrode layer, the cap layer, the free layer, the tunnel barrier layer, the reference layer, and the bottom electrode layer to form a magnetoresistive random access memory cell.
A method comprising:
- forming a perpendicular magnetic tunnel junction stack over a bottom electrode layer, the perpendicular magnetic tunnel junction stack comprising:
- a reference layer;
- a tunnel barrier layer over the reference layer, the tunnel barrier layer comprising a first composition of magnesium and oxygen;
- a free layer over the tunnel barrier layer;
- and
- a cap layer over the free layer, the cap layer comprising a second composition of magnesium and oxygen, the second composition of magnesium and oxygen having a greater atomic concentration of oxygen and a lesser atomic concentration of magnesium than the first composition of magnesium and oxygen;
- forming a top electrode layer on the perpendicular magnetic tunnel junction stack;
- and
- patterning the top electrode layer, the perpendicular magnetic tunnel junction stack, and the bottom electrode layer to form a magnetoresistive random access memory cell.
Dependencies are inferred from the claim text.