Method of fabricating a memory device
AssigneeImec Vzw
InventorsRoman Izmailov, Amey Mahadev Walke, Farrukh Yasin
Life of this patent
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Abstract
In one aspect, a method of fabricating a memory device, for example, a ferroelectric memory device is provided. In another aspect, a structure suitable for building the memory device is provided. The method can include a replacement metal gate (RMG) process, where sacrificial layers of a stack are replaced with metal layers. The RMG process can be performed before a process of forming memory structures in memory holes, which extend through the stack. In this way, the memory structures can be formed with low thermal budget, for instance, at temperatures below 400° C., which can be of benefit particularly for ferroelectric layers of memory structures of a ferroelectric memory device.
Claims20
A method of fabricating a memory device, the method comprising:
- depositing a stack of a plurality of dielectric layers and sacrificial layers alternatingly arranged on one another along a stacking direction, wherein the sacrificial layers comprise a first sacrificial material;
- forming a plurality of memory holes in the stack, wherein each memory hole extends through the plurality of dielectric and sacrificial layers of the stack;
- filling each memory hole with a second sacrificial material;
- shaping the stack to have a staircase structure at opposite outer sides, wherein the staircase structure comprises multiple layer pairs of a dielectric layer and a sacrificial layer of the plurality of dielectric and sacrificial layers, wherein a respective width of the layer pairs decreases along the stacking direction;
- after forming the memory holes, replacing each sacrificial layer of the plurality of sacrificial layers of the stack with a respective metal layer of a plurality of metal layers;
- and
- after replacing the sacrificial layers, replacing the second sacrificial material in each memory hole with a respective memory structure;
- wherein each memory structure of a plurality of memory structures forms, in combination with the plurality of metal layers, a plurality of memory cells.
A structure suitable for building a memory device, the structure comprising:
- a stack of a plurality of metal layers and dielectric layers alternatingly arranged on one another along a stacking direction,
- wherein the stack has a shape of a staircase structure at opposite outer sides of the stack, wherein the shape of the staircase structure is formed by the stack having multiple layer pairs of a dielectric layer and a metal layer of the plurality of dielectric and metal layers, wherein a respective width of the layer pairs decreases along the stacking direction;
- and
- a plurality of memory holes in the stack, wherein each memory hole extends through the plurality of dielectric and metal layers of the stack, and wherein each memory hole is filled with a sacrificial material.
Dependencies are inferred from the claim text.