Structure and method to fabricate a body contact
View Patent ↗A structure and method to fabricate a body contact on a transistor is disclosed. The method comprises forming a semiconductor structure with a transistor on a handle wafer. The structure is then inverted, and the handle wafer is removed. A silicided body contact is then formed on the transistor in the inverted position. The body contact may be connected to neighboring vias to connect the body contact to other structures or levels to form an integrated circuit.
1. A method for fabricating a body contact on a transistor having a body, source, drain, and gate, the transistor disposed on a dielectric layer, comprising:
forming a cavity in the dielectric layer to expose a portion of the body of the transistor;
forming a silicide layer on the exposed portion of the body;
depositing a metal liner on the silicide layer;
and depositing a layer of polysilicon on the metal liner.
2. The method of claim 1 , further comprising: disposing the dielectric layer on a handle wafer; inverting the handle wafer; and removing the handle wafer, prior to forming a cavity in the dielectric layer to expose a portion of the body of the transistor.
3. The method of claim 2 , further comprising: applying a mask layer over the dielectric layer; lithographically patterning the mask layer to form a void in the mask layer, above the exposed portion of the body; and wherein forming a cavity in the dielectric layer to expose a portion of the body of the transistor comprises etching the dielectric layer.
4. The method of claim 3 , wherein etching the dielectric layer is performed with a reactive ion etch.
5. The method of claim 3 , further comprising removing the mask layer after etching the dielectric layer.
6. The method of claim 1 , wherein forming a silicide layer comprises forming a nickel silicide layer.
7. The method of claim 1 , wherein forming a silicide layer comprises forming a cobalt silicide layer.
8. The method of claim 1 , wherein the step of depositing a metal liner comprises depositing a liner comprising titanium.
9. The method of claim 1 , wherein depositing a metal liner comprises depositing a liner comprising copper.
10. The method of claim 1 , wherein depositing a metal liner is performed via atomic layer deposition.
11. The method of claim 1 , wherein depositing a metal liner is performed via chemical vapor deposition.
12. A method for fabricating a body contact on a transistor having a body, source, drain, and gate, the transistor disposed on a dielectric layer, comprising:
forming a cavity in the dielectric layer to expose a portion of the body of the transistor;
forming a cavity in the dielectric layer to expose an active silicon area;
forming a silicide layer on the exposed portion of the body;
depositing a metal liner on the silicide layer;
depositing a polysilicon layer on the metal liner; and
forming a void in the polysilicon layer, the void disposed between the body and the active silicon area.