Multi-level phase change random access memory device
AssigneeSamsung Electronics Co., Ltd.
InventorTae-Yon Lee
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Abstract
A multi-level phase change random access memory device includes a first electrode, a second electrode, and a phase change material disposed between the first electrode and the second electrode. The multi-level phase change random access memory device also includes a variable bias source coupled to the first electrode. The variable bias source provides a respective bias applied at the first electrode to form a portion of the phase change material to have one of an amorphous state and different crystal states for storing multi-bits data.
Claims20
A multi-level phase change random access memory device comprising:
- a first electrode;
- a second electrode;
- a phase change material disposed between the first electrode and the second electrode;
- and
- a variable bias source coupled to the first electrode,
- wherein the variable bias source provides a respective bias applied at the first electrode to control a portion of the phase change material to have one of an amorphous state and at least two different crystal phases from respective polymorphic phase transformations,
- and wherein said different crystal phases are polymorphic phase transformations with different ionic resistivities from each-other such that said phase change material does not have any portion with a same ionic resistivity in said different crystal phases.
A multi-level phase change random access memory device comprising:
- a first electrode;
- a second electrode;
- a phase change material disposed between the first electrode and the second electrode;
- a variable bias source coupled to the first electrode;
- and
- a voltage source controller that controls the variable bias source to provide different respective biases applied at the first electrode for different bit patterns of at least two data bits to control a portion of the phase change material to have one of an amorphous state and at least two different crystal phases from respective polymorphic phase transformations,
- wherein a constant bias is applied at the second electrode for the different bit patterns
- and wherein said different crystal phases are polymorphic phase transformations with different ionic resistivities from each-other such that said phase change material does not have any portion with a same ionic resistivity in said different crystal phases.
Dependencies are inferred from the claim text.