Method of forming a small contact in phase-change memory and a memory cell produced by the method
OwnerHsiang-Lan Lunginventor
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Abstract
A method of fabricating a phase-change memory cell is described. The cross-sectional area of a contact with a phase-change memory element within the cell is controlled by a width and an exposed length of a bottom electrode. The method allows the formation of very small phase-change memory cells.
Claims28
A method of forming a memory cell, comprising:
- forming a bottom electrode above a substrate, the bottom electrode having a first dimension and a second dimension;
- covering a first portion of the bottom electrode and exposing a second portion of the bottom electrode such that the second portion has a width equal to the first dimension and an exposed length less than or equal to the second dimension;
- and
- disposing a phase-change material on the second portion of the bottom electrode, thereby forming a contact between the phase-change material and the bottom electrode, the contact having an area equal to a product of the width and the exposed length.
A memory cell, comprising:
- a bit line disposed within a substrate;
- an isolation device formed above and making contact with the bit line;
- a bottom electrode formed above the isolation device, the bottom electrode having a width and an exposed length;
- and
- a phase-change material disposed on the bottom electrode, such that a contact between the bottom electrode and the phase-change material has a cross-sectional area equal to a product of the width and the exposed length.
An array of memory cells, comprising bit lines disposed in a reference direction, word lines disposed in a direction other than the reference direction, and memory cells at intersections of bit lines and word lines, each memory cell comprising:
- a bottom electrode having a width and an exposed length, the bottom electrode being disposed between one of the word lines and one of the bit lines at one of the intersections;
- and
- a phase-change material disposed on the bottom electrode, such that a contact between the bottom electrode and the phase-change material has a cross-sectional area equal to a product of the width and the exposed length.
A method of operating a memory cell, comprising:
- resetting the memory cell by applying an amorphizing current pulse to the memory cell such that a temperature of a phase-change memory element within the memory cell is raised above a first temperature and such that the temperature of the phase-change memory element is caused to remain above a second temperature less than the first temperature for a first time interval;
- and
- setting the memory cell by applying a crystallizing current pulse to the memory cell such that the temperature of the phase-change memory element is raised to a temperature above the second temperature and such that the temperature of the phase-change memory element is caused to remain above the second temperature for at least a second time interval, the duration of the second time interval being greater than the duration of the first time interval.
Dependencies are inferred from the claim text.