Self-selecting PCM device not requiring a dedicated selector transistor
View Patent ↗A Zinc Oxide (ZnO) layer deposited using Atomic Layer Deposition (ALD) over a phase-change material forms a self-selected storage device. The diode formed at the ZnO/GST interface shows both rectification and storage capabilities within the PCM architecture.
1. A Phase-Change Memory (PCM), comprising:
a first metal line;
a second metal line;
a dielectric between the first and second metal lines;
a first barrier between the first metal line and the dielectric and contacting the first metal line and the dielectric;
a second barrier between the second metal line and the dielectric and contacting the second metal line and the dielectric;
a first memory cell having an oxide-based material including an n-type Zinc Oxide (ZnO) material in direct contact with a natural p-type crystalline PCM material to form a diode junction embedded in the PCM material, the ZnO material contacting the first metal line;
first material arranged in a stack with the ZnO material and the PCM material;
a second memory cell having an oxide-based material including an n-type ZnO material in direct contact with a natural p-type crystalline PCM material to form a diode junction embedded in the PCM material, the ZnO material contacting the second metal line; and
a second material arranged in a stack with the ZnO material and the PCM material of the second memory cell.
2. The PCM of claim 1 wherein each of the first and second metal lines includes copper.
3. The PCM of claim 1 wherein a positive bias of two volts or less forward biases the diode junction to allow detection of a state of the memory cell by reading a resistance of the PCM material.
4. The PCM of claim 1 wherein the first material includes TiN.
5. The PCM of claim 1 wherein the second material includes TiN.
6. The PCM of claim 1 wherein the PCM material is deposited directly above the ZnO material.