Forming nonvolatile phase change memory cell having a reduced thermal contact area
First Claim
1. A monolithic three dimensional phase change memory array comprising:
- a) a first memory level, the first memory level comprising;
i) a plurality of substantially parallel first conductors formed at a first height above a substrate;
ii) a plurality of substantially parallel second conductors formed at a second height, the second height above the first height;
iii) a plurality of first diodes, each disposed between one of the first conductors and one of the second conductors;
iv) a plurality of heater layers, each disposed between one of the first conductors and one of the second conductors and each having an upper surface having a first area;
v) a plurality of phase change elements, each having a lower surface having a second area,wherein at least a part of the lower surface of each phase change element is in contact with the upper surface of the adjacent heater layer andwherein the first area is smaller than the second area; and
b) at least a second memory level monolithically formed on the first memory level.
5 Assignments
0 Petitions
Accused Products
Abstract
The invention provides for a nonvolatile memory cell comprising a heater layer in series with a phase change material, such as a chalcogenide. Phase change is achieved in chalcogenide memories by thermal means. Concentrating thermal energy in a relatively small volume assists this phase change. In the present invention, a layer in a pillar-shaped section of a memory cell is etched laterally, decreasing its cross-section. In this way the cross section of the contact area between the heater layer and the phase change material is reduced. In preferred embodiments, the laterally etched layer is the heater layer or a sacrificial layer. In a preferred embodiment, such a cell can be used in a monolithic three dimensional memory array.
-
Citations
14 Claims
-
1. A monolithic three dimensional phase change memory array comprising:
-
a) a first memory level, the first memory level comprising; i) a plurality of substantially parallel first conductors formed at a first height above a substrate; ii) a plurality of substantially parallel second conductors formed at a second height, the second height above the first height; iii) a plurality of first diodes, each disposed between one of the first conductors and one of the second conductors; iv) a plurality of heater layers, each disposed between one of the first conductors and one of the second conductors and each having an upper surface having a first area; v) a plurality of phase change elements, each having a lower surface having a second area, wherein at least a part of the lower surface of each phase change element is in contact with the upper surface of the adjacent heater layer and wherein the first area is smaller than the second area; and b) at least a second memory level monolithically formed on the first memory level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
Specification