Ferromagnetic tunnel junction device and method of forming the same
First Claim
1. An intermediate layer sandwiched between first and second ferromagnetic layers, said intermediate layer having at least a single oxide layered region forming at least a single tunnel barrier, said at least single oxide layered region which has at least a first abrupt interface with said first ferromagnetic layer and a second abrupt interface with said second ferromagnetic layer,wherein each of said first and second interfaces has such an extremely high abruptness as a monoatomic layer level that a width of a boundary area between an oxygen atom containing region and an oxygen atom free region is substantially the same as a boundary between adjacent two monoatomic layers.
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Abstract
The invention provides a method of forming a tunnel barrier layer comprising at least a single oxide layered region in an intermediate layer sandwiched between first and second ferromagnetic layers. The method comprises the following steps. An electrically conductive layer is formed on the first ferromagnetic layer. The electrically conductive layer is subjected to an exactly pure oxygen gas prepared by having introduced oxygen into a vacuum, so as to cause a natural oxidation of the electrically conductive layer, thereby to form an oxide layer forming a tunnel barrier. The second ferromagnetic layer is formed on the oxide layer.
22 Citations
27 Claims
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1. An intermediate layer sandwiched between first and second ferromagnetic layers, said intermediate layer having at least a single oxide layered region forming at least a single tunnel barrier, said at least single oxide layered region which has at least a first abrupt interface with said first ferromagnetic layer and a second abrupt interface with said second ferromagnetic layer,
wherein each of said first and second interfaces has such an extremely high abruptness as a monoatomic layer level that a width of a boundary area between an oxygen atom containing region and an oxygen atom free region is substantially the same as a boundary between adjacent two monoatomic layers.
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13. A multi-layer structure in a ferromagnetic tunnel junction device, said multi-layer structure comprising:
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first and second ferromagnetic layers; and
an intermediate layer sandwiched between said first and second ferromagnetic layers, said intermediate layer comprising an oxide layer which forms a single tunnel barrier, said oxide layer having a first abrupt interface with said first ferromagnetic layer and a second abrupt interface with said second ferromagnetic layer, wherein each of said first and second interfaces has such an extremely high abruptness as a monoatomic layer level that a width of a boundary area between an oxygen atom containing region and an oxygen atom free region is substantially the same as a boundary between adjacent two monoatomic layers. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A multi-layer structure in a ferromagnetic tunnel junction device, said multi-layer structure comprising:
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first and second ferromagnetic layers; and
an intermediate layer sandwiched between said first and second ferromagnetic layers, said intermediate layer comprising an electrically conductive intermediate layered region and first and second oxide layered regions sandwiching said electrically conductive intermediate layered region so that said first and second oxide layered regions form double tunnel barriers and said electrically conductive intermediate layered region forms a single potential well defined between said double tunnel barriers, said first oxide layered region having a first abrupt interface with said first ferromagnetic layer and said second oxide region having a second abrupt interface with said second ferromagnetic layer, wherein each of said first and second interfaces has such an extremely high abruptness as a monoatomic layer level that a width of a boundary area between an oxygen atom containing region and an oxygen atom free region is substantially the same as a boundary between adjacent two monoatomic layers. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification