Method of fabricating a DRAM capacitor
AssigneeUnited Microelectronics Corp.
InventorsTing-Chang Chang, Cheng-Jer Yang
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Abstract
A method of fabricating a DRAM capacitor. A silicon germanium layer is formed on a lower electrode of the capacitor. The silicon germanium layer is oxidized to form a segregated grained germanium layer and a silicon oxide layer where the segregated grained germanium is distributed on the lower electrode. The silicon oxide layer is then removed. Using the segregated grained germanium as a hard mask, the lower electrode is etched to a depth to form a multi-cylinder structure. The segregated grained germanium is then removed. A capacitor dielectric layer and an upper electrode are successively formed on the multi-cylinder structure.
Claims20
A method of fabricating a DRAM capacitor, comprising:
- providing a substrate having a doped region;
- forming an insulating layer over the substrate where the insulating layer has a contact window to expose the doped region;
- forming a first conductive layer to fill the contact window;
- forming a silicon germanium layer on the first conductive layer;
- forming a segregated grained germanium in the silicon germanium layer on the first conductive layer and the silicon germanium layer being transformed into a silicon oxide layer on the first conductive layer;
- removing the silicon oxide layer;
- forming a multi-cylinder lower electrode by removing the first conductive layer to a depth using the segregated grained germanium as a mask;
- removing the segregated grained germanium;
- forming a capacitor dielectric layer on the multi-cylinder lower electrode;
- and
- forming a second conductive layer on the capacitor dielectric layer to serve as an upper electrode.
A method of fabricating a lower electrode of a DRAM capacitor adapted for a substrate where the substrate has an insulating layer formed thereon, a first conductive being disposed on the insulating layer and electrically connecting to the substrate through a contact within the insulating layer, comprising:
- forming a silicon germanium layer on the first conductive layer;
- oxidizing the silicon germanium layer to form a segregated grained germanium on the first insulating layer and a silicon oxide layer;
- removing the silicon oxide layer;
- etching the first conductive layer to a depth by using the segregated grained germanium layer as a mask to form a multi-cylinder lower electrode;
- removing the segregated grained germanium layer.
Dependencies are inferred from the claim text.