MgO/NiFe MTJ for high performance MRAM application
AssigneeMagIC Technologies, Inc.
InventorsCheng T. Horng, Ru-Ying Tong
Life of this patent
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Abstract
An improved tunneling barrier layer is formed for use in a MTJ device. This is accomplished by forming the tunneling barrier layer in two steps. First a layer of magnesium is deposited by DC sputtering and converted to magnesium oxide through radical oxidation. This is followed by a second, thinner, magnesium layer that is converted to magnesium oxide through normal oxidation. Optionally, there may also be a thin layer of magnesium on the two magnesium oxide layers.
Claims23
A method to form a tunneling barrier layer, comprising:
- by means of D.C. sputtering, depositing a first magnesium layer to a first thickness;
- fully oxidizing said first magnesium layer by means of radical oxidation, thereby forming a first layer of magnesium oxide;
- depositing a second magnesium layer to a second thickness on said first magnesium oxide layer;
- then fully oxidizing said second magnesium layer by means of natural oxidation, thereby forming said tunneling barrier layer;
- and
- annealing said tunneling barrier layer in a magnetic field having a direction, whereby said first magnesium oxide layer has a preferred 001 crystal orientation.
A method to form a tunneling barrier layer, comprising:
- by means of D.C. sputtering, depositing a first magnesium layer to a first thickness;
- fully oxidizing said first magnesium layer by means of a first radical oxidation, thereby forming a first layer of magnesium oxide;
- depositing a second magnesium layer to a second thickness on said first magnesium oxide layer;
- fully oxidizing said second magnesium layer by means of a second radical oxidation, thereby forming a second layer of magnesium oxide;
- and
- depositing a third magnesium layer to a third thickness on said second magnesium oxide layer thereby completing formation of said tunneling barrier layer.
A process to manufacture a magnetic tunnel junction memory element, including a tunneling barrier layer, comprising:
- providing a seed layer on a lower electrode;
- depositing an antiferromagnetic layer on said seed layer;
- depositing a pinned layer on said antiferromagnetic layer;
- by means of D.C. sputtering, depositing a first magnesium layer, having a first thickness, on said pinned layer;
- fully oxidizing said first magnesium layer by means of radical oxidation, thereby forming a first layer of magnesium oxide;
- annealing said first magnesium oxide layer in a magnetic field having a direction, whereby said first magnesium oxide layer acquires a preferred 001 crystal orientation;
- depositing a second magnesium layer to a second thickness on said first magnesium oxide layer;
- then fully oxidizing said second magnesium layer by means of natural oxidation, thereby forming a magnesium oxide tunneling barrier layer having a thickness between about 3 and 5 Angstroms;
- depositing a free layer on said tunneling barrier layer;
- and
- depositing a capping layer on said free layer.
A method to form a tunneling barrier layer, comprising:
- by means of D.C. sputtering, depositing a first magnesium layer to a thickness of from about 10 to 13 Angstroms;
- fully oxidizing said first magnesium layer by means of radical oxidation, thereby forming a first layer of magnesium oxide;
- on said first magnesium oxide layer, depositing a second magnesium layer to a thickness of from about 3 to 5 Angstroms;
- then fully oxidizing said second magnesium layer by means of radical oxidation, thereby forming a second layer of magnesium oxide;
- on said second magnesium oxide layer, depositing a third magnesium layer to a thickness of from about 3 to 4 Angstroms, thereby completing formation of said tunneling barrier layer;
- and
- annealing said tunneling barrier layer in a magnetic field having a direction, whereby said first magnesium oxide layer has a preferred 001 crystal orientation and said third magnesium layer acts to getter oxygen away from both said second magnesium oxide layer and from a subsequently deposited free layer.
Dependencies are inferred from the claim text.