MgO/NiFe MTJ for high performance MRAM application
First Claim
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1. 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.
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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.
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Citations
23 Claims
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1. A method to form a tunneling barrier layer, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method to form a tunneling barrier layer, comprising:
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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. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A process to manufacture a magnetic tunnel junction memory element, including a tunneling barrier layer, comprising:
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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. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A method to form a tunneling barrier layer, comprising:
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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.
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Specification