Nonvolatile ferroelectric memory device and method for manufacturing the same
A nonvolatile ferroelectric memory device includes a plurality of unit cells. Each of the unit cells includes a cell capacitor and a cell transistor. The cell capacitor includes a storage node, a ferroelectric layer, and a plate line. The cell capacitors of more than one of the plurality of unit cells are provided in a trench.
1. A method for manufacturing a nonvolatile ferroelectric memory device having a cell array block including a plurality of unit cells, the method comprising:
forming cell transistors on a semiconductor substrate;
forming contact nodes for connecting cell capacitors to the cell transistors;
forming a first insulating film over the cell transistors and the contact nodes;
selectively etching the first insulating film to form trenches, wherein each of the trenches exposes a plurality of contact nodes;
forming a plurality of storage nodes connected to the plurality of contact nodes on an inner surface of each of the trenches, wherein the storage nodes are separated from each other and the plurality of storage nodes that are separated from each other are formed on an inner surface of each of the trenches, each storage node formed to be L-shaped on an inner surface of each of the trenches;
forming a ferroelectric layer over the storage nodes; and
forming a plate line over the ferroelectric layer.
2. The method according to claim 1 , wherein the contact nodes are formed by a plug process.
3. The method according to claim 1 , wherein the storage nodes are separated from each other by an insulating film.
4. The method according to claim 1 , wherein the storage nodes are separated from each other by the ferroelectric layer.
5. The method according to claim 1 , wherein the storage nodes are separated from each other by a damascene process.
6. The method according to claim 1 , wherein the storage nodes are separated from each other by an etch-back process.
7. The method according to claim 1 , wherein the storage nodes are separated from each other by a planarization process.
8. The method according to claim 1 , wherein the plate line is formed by chemical vapor deposition or atomic layer deposition.