Method for programming a multilevel phase change memory device
First Claim
1. A method of programming a phase change device comprising:
- selecting a desired threshold voltage (Vth); and
applying a programming pulse to a phase change material in the phase change device including;
applying a quantity of energy to the phase change material to drive at least a portion of the phase change material above a melting energy level, the quantity of energy being applied for a first time interval;
allowing a portion of the energy applied to the phase change material to dissipate below the melting energy level;
controlling a shape of an energy dissipation from the phase change material until the energy applied to the phase change material is less than a quenched energy level, wherein the shape of the energy dissipation is controlled to cause the phase change device to have the desired Vth; and
allowing a remaining portion of the energy applied to the phase change material to dissipate to an environmental level.
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Abstract
A method of programming a phase change device includes selecting a desired threshold voltage (Vth) and applying a programming pulse to a phase change material in the phase change device. The applying of the programming pulse includes applying a quantity of energy to the phase change material to drive at least a portion of this material above a melting energy level. A portion of the energy applied to the phase change material is allowed to dissipate below the melting energy level. The shape of the energy dissipation from the phase change material is controlled until the energy applied to the phase change material is less than a quenched energy level, to cause the phase change device to have the desired Vth. A remaining portion of the energy applied to the phase change material is allowed to dissipate to an environmental level.
24 Citations
21 Claims
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1. A method of programming a phase change device comprising:
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selecting a desired threshold voltage (Vth); and applying a programming pulse to a phase change material in the phase change device including; applying a quantity of energy to the phase change material to drive at least a portion of the phase change material above a melting energy level, the quantity of energy being applied for a first time interval; allowing a portion of the energy applied to the phase change material to dissipate below the melting energy level; controlling a shape of an energy dissipation from the phase change material until the energy applied to the phase change material is less than a quenched energy level, wherein the shape of the energy dissipation is controlled to cause the phase change device to have the desired Vth; and allowing a remaining portion of the energy applied to the phase change material to dissipate to an environmental level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of programming a multi-state phase change device comprising:
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selecting a desired threshold voltage (Vth), from a plurality of desired Vths, each one of the plurality of desired Vths corresponding to one of a plurality of data values; and applying a programming pulse to a phase change material in the phase change device including; applying a quantity of energy to the phase change material to drive at least a portion of the phase change material above a melting energy level, the quantity of energy being applied for a first time interval; allowing a portion of the energy applied to the phase change material to dissipate below the melting energy level; controlling a shape of an energy dissipation from the phase change material until the energy applied to the phase change material is less than a quenched energy level, wherein the shape of the energy dissipation is controlled to cause the phase change device to have the desired Vth; and allowing a remaining portion of the energy applied to the phase change material to dissipate to an environmental level. - View Dependent Claims (16, 17)
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18. A method of programming a memory array comprising:
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selecting a desired threshold voltage (Vth); and applying a programming pulse to a phase change memory device in the memory array, wherein a steering element applies the programming pulse to the phase change memory device including; applying a quantity of energy to the phase change device to drive at least a portion of a phase change material in the phase change device above a melting energy level, the quantity of energy being applied for a first time interval; allowing a portion of the energy applied to the phase change material to dissipate below the melting energy level; controlling a shape of an energy dissipation from the phase change material until the energy applied to the phase change material is less than a quenched energy level, wherein the shape of the energy dissipation is controlled to cause the phase change device to have the desired Vth; and allowing a remaining portion of the energy applied to the phase change material to dissipate to an environmental level. - View Dependent Claims (19, 20, 21)
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Specification