Magnetic random access memory devices having titanium-rich lower electrodes with oxide layer and oriented tunneling barrier
First Claim
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1. A magnetic tunnel junction structure for a magnetic random access memory comprising:
- a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer;
an oxide layer on the lower electrode; and
a magnetic tunnel junction on the oxide layer, the magnetic tunnel junction comprising;
a fixed layer including a seed layer;
a tunneling barrier on the seed layer, that is oriented in a same crystalline direction as a most closely packed plane direction of the seed layer, the surface roughness of the tunneling barrier being reduced by the lower surface roughness of the Ti-rich TiN layer; and
a free layer on the tunneling barrier.
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Abstract
Magnetic Random Access Memory (MRAM) devices include a lower electrode and a magnetic tunnel junction on the lower electrode. The magnetic tunnel junction includes a seed layer and a tunneling barrier that is oriented in a same direction as the most closely packed plane direction of the seed layer. An oxide layer may be provided between the lower electrode and the magnetic tunnel junction. The lower electrode may be a titanium-rich TiN layer having more than 50 atomic percent titanium content. Analogous fabrication methods are also described.
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Citations
14 Claims
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1. A magnetic tunnel junction structure for a magnetic random access memory comprising:
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a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer; an oxide layer on the lower electrode; and a magnetic tunnel junction on the oxide layer, the magnetic tunnel junction comprising; a fixed layer including a seed layer; a tunneling barrier on the seed layer, that is oriented in a same crystalline direction as a most closely packed plane direction of the seed layer, the surface roughness of the tunneling barrier being reduced by the lower surface roughness of the Ti-rich TiN layer; and a free layer on the tunneling barrier. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A magnetic tunnel junction structure of a Magnetic Random Access Memory (MRAM) device, comprising:
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a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer; and a magnetic tunnel junction on the lower electrode, the magnetic tunnel junction comprising a seed layer and a tunneling barrier that is oriented in a same direction as a most closely packed plane direction of the seed layer, the surface roughness of the tunneling barrier being reduced by the lower surface roughness of the Ti-rich TiN layer. - View Dependent Claims (9)
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10. A magnetic tunnel junction structure of a Magnetic Random Access Memory (MRAM) device, comprising:
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a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer; an oxide layer on the lower electrode; and a magnetic tunnel junction on the oxide layer.
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11. A magnetic tunnel junction structure of a Magnetic Random Access Memory (MRAM) device, comprising:
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a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer; and a magnetic tunnel junction on the lower electrode. - View Dependent Claims (12)
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13. A magnetic tunneling junction structure of a Magnetic Random Access Memory (MRAM) device, comprising:
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a lower electrode that comprises a Ti-rich TiN layer having a titanium (Ti) content of between about 70 and about 90 atomic percent, the Ti-rich TiN layer having a lower chemical mechanical polishing rate than a stoichiometric TiN layer and having a surface roughness that is also lower than a stoichiometric TiN layer; and a magnetic tunnel junction on the lower electrode, the magnetic tunnel junction comprising a seed layer and a tunneling barrier that is oriented in a same direction as a most closely packed plane direction of the seed layer, the surface roughness of the tunneling barrier being reduced by the lower surface roughness of the Ti-rich TiN layer. - View Dependent Claims (14)
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Specification