Magnetic tunnel junction device
First Claim
1. A method of manufacturing a magnetic tunnel junction (MTJ) device, comprising:
- forming a first CoFeB layer that is amorphous;
forming a magnesium oxide (MgO) layer over the first CoFeB layer;
forming a second CoFeB layer that is amorphous over the MgO layer; and
annealing the first and second CoFeB layers and the MgO layer,wherein the first and second CoFeB layers are crystallized by the annealing, andwherein the MgO layer is poly-crystalline in which a (001) crystal plane is preferentially oriented.
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Abstract
The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.
82 Citations
15 Claims
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1. A method of manufacturing a magnetic tunnel junction (MTJ) device, comprising:
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forming a first CoFeB layer that is amorphous; forming a magnesium oxide (MgO) layer over the first CoFeB layer; forming a second CoFeB layer that is amorphous over the MgO layer; and annealing the first and second CoFeB layers and the MgO layer, wherein the first and second CoFeB layers are crystallized by the annealing, and wherein the MgO layer is poly-crystalline in which a (001) crystal plane is preferentially oriented. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of manufacturing a magnetic tunnel junction (MTJ) device, comprising:
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forming a first ferromagnetic layer including a first CoFeB layer that is amorphous; forming a barrier layer including a magnesium oxide (MgO) layer to have a poly-crystalline state in which a (001) crystal plane is preferentially oriented over the first ferromagnetic layer; forming a second ferromagnetic layer including a second CoFeB layer that is amorphous over the barrier layer; and annealing the first and second ferromagnetic layers and the barrier layer, to crystallize the first and second CoFeB layers. - View Dependent Claims (12, 13, 14, 15)
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Specification