Conductive contacts in semiconductor on insulator substrate
A semiconductor device includes a gate stack arranged on a channel region of a semiconductor layer and a semiconductor layer arranged on an insulator layer. A crystalline source/drain region is arranged in a cavity in the insulator layer, and a spacer is arranged adjacent to the gate stack, the spacer arranged over the source/drain region. A second insulator layer is arranged on the spacer and the gate stack, and a conductive contact is arranged in the source/drain region.
1. A semiconductor device comprising:
a gate stack on a channel region of a semiconductor layer;
the semiconductor layer on an insulator layer;
a crystalline source/drain region in a first cavity in the insulator layer;
a spacer adjacent to the gate stack, the spacer positioned on the source/drain region such that the spacer defines an L-shape and a bottommost edge of the L-shape is coplanar to a surface of the source/drain region;
an inter-level dielectric layer over the gate stack and a portion of the source/drain region; and
a conductive contact in a second cavity in the inter-level dielectric layer, the second cavity defined by the source/drain region and the spacer.
2. The device of claim 1 , wherein the first cavity in the insulator layer is an undercut region defined by the insulator layer and the semiconductor layer.
3. The device of claim 2 , wherein the semiconductor layer includes a doped semiconductor region.
4. The device of claim 3 , wherein the second cavity in the inter-level dielectric layer and the source/drain region exposes a portion of the spacer.
5. The device of claim 4 , wherein the second cavity in the inter-level dielectric layer and the source/drain region exposes a portion of the doped semiconductor region.
6. The device of claim 5 , wherein the conductive contact includes dopants.
7. The device of claim 6 , wherein the spacer includes a nitride.
8. The device of claim 6 , wherein the spacer includes an oxide.
9. A semiconductor device comprising:
a gate stack on a channel region of a semiconductor layer;
the semiconductor layer on an insulator layer, the semiconductor layer including a doped semiconductor region;
a crystalline source/drain region in a first cavity in the insulator layer;
a spacer adjacent to the gate stack, the spacer being over the source/drain region;
an inter-level dielectric layer over the gate stack and a portion of the source/drain region;
a conductive contact in a second cavity in the inter-level dielectric layer and the source/drain region, the second cavity including an undercut region defined by the spacer, the doped semiconductor region, and the source/drain region.
10. The device of claim 9 , wherein the spacer defines an L-shape.
11. The device of claim 10 , wherein the first cavity is an undercut region defined by the insulator layer and the semiconductor layer.
12. The device of claim 11 , wherein the conductive contact includes dopants.
13. The device of claim 12 , wherein the spacer includes a nitride.
14. The device of claim 12 , wherein the spacer includes an oxide.