REDUCING SOURCE LOADING EFFECT IN SPIN TORQUE TRANSFER MAGNETORESISTIVE RANDOM ACCESS MEMORY (STT-MRAM)
First Claim
1. An apparatus comprising:
- a memory cell comprising;
a magnetic tunnel junction (MTJ) structure including;
a free layer coupled to a bit line; and
a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state,wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line.
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Accused Products
Abstract
A memory cell comprises a magnetic tunnel junction (MTJ) structure that includes a free layer coupled to a bit line and a pinned layer. A magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state. The pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line.
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Citations
21 Claims
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1. An apparatus comprising:
a memory cell comprising; a magnetic tunnel junction (MTJ) structure including; a free layer coupled to a bit line; and a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state, wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus comprising:
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means for storing a data value as an orientation of a magnetic moment that is programmable by a spin polarized current exceeding a threshold current density, the means for storing the data value coupled to a bit line; and means for storing a pinned magnetic moment having a pinned orientation, wherein the magnetic moment that is programmable is substantially parallel to the pinned magnetic moment in a first state and substantially antiparallel to the pinned magnetic moment in a second state, wherein the means for storing the pinned magnetic moment has a physical dimension to produce an offset magnetic field corresponding to a first switching current to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line. - View Dependent Claims (8, 9)
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10. An apparatus comprising:
a memory device comprising; a plurality of memory cells, wherein at least one memory cell of the plurality of memory cells comprises; a magnetic tunnel junction (MTJ) structure, wherein a magnetic moment of a free layer of the MTJ structure is substantially parallel to a magnetic moment of a pinned layer of the MTJ structure in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state; and an access transistor coupled to the MTJ structure, wherein a ratio of a magnitude of a first switching current to switch the MTJ structure from the first state to the second state is less than half of a second switching current to switch the MTJ structure from the second state to the first state. - View Dependent Claims (11, 12)
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13. A method comprising:
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receiving design information representing at least one physical property of a semiconductor device, the semiconductor device including a magnetic tunnel junction (MTJ) structure including; a free layer coupled to a bit line; and a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state, wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line; transforming the design information to comply with a file format; and generating a data file including the transformed design information. - View Dependent Claims (14)
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15. A method comprising:
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receiving a data file including design information corresponding to a semiconductor device; and fabricating the semiconductor device according to the design information, wherein the semiconductor device includes a magnetic tunnel junction (MTJ) structure including; a free layer coupled to a bit line; and a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state, wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line. - View Dependent Claims (16)
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17. A method comprising:
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receiving design information including physical positioning information of a packaged semiconductor device on a circuit board, the packaged semiconductor device including a semiconductor structure comprising a magnetic tunnel junction (MTJ) structure including; a free layer coupled to a bit line; and a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state, wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line; and transforming the design information to generate a data file. - View Dependent Claims (18)
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19. A method comprising:
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receiving a data file including design information including physical positioning information of a packaged semiconductor device on a circuit board; and manufacturing the circuit board configured to receive the packaged semiconductor device according to the design information, wherein the packaged semiconductor device comprises a magnetic tunnel junction (MTJ) structure including; a free layer coupled to a bit line; and a pinned layer, wherein a magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state, wherein the pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line. - View Dependent Claims (20, 21)
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Specification