Deep trench polysilicon fin first
After forming a recessed conductive material portion over a deep trench capacitor located in a lower portion of a deep trench embedded in a substrate, a hard mask layer is formed over a top semiconductor layer of the substrate and the recessed conductive material portion such that the hard mask layer completely fills the deep trench. Next, the hard mask layer, the top semiconductor layer and the recessed conductive material portion are patterned to form a laterally contacting pair of a semiconductor fin and a conductive strap structure over the deep trench capacitor as well as a dielectric cap embedded in the deep trench. The dielectric cap vertically contacts a lower portion of the conductive strap structure and laterally surrounds a portion of an upper portion of the conductive strap structure that is not in contact with the semiconductor fin.
1. A semiconductor structure comprising:
a semiconductor fin located on a substrate;
a deep trench capacitor embedded in said substrate;
a conductive strap structure overlying said deep trench capacitor, wherein said conductive strap structure comprises a lower portion vertically contacting topmost surfaces of said deep trench capacitor and an upper portion adjoined a portion of said lower portion, said upper portion having a first portion laterally contacting said semiconductor fin and a second portion underlying said first portion contacting a portion of said lower portion; and
a dielectric cap embedded in said substrate, said dielectric cap vertically contacting another portion of said lower portion of said conductive strap structure and laterally surrounding said second portion of said upper portion of said conductive strap structure,
wherein a bottom surface of said semiconductor fin and a top surface of said dielectric cap are coplanar with a topmost surface of said substrate.
2. The semiconductor structure of claim 1 , wherein said deep trench capacitor comprises an inner electrode, a node dielectric, and an outer electrode.
3. The semiconductor structure of claim 1 , wherein said conductive strap structure comprises a doped elemental semiconductor material, a doped compound semiconductor material, or an alloy thereof.
4. The semiconductor structure of claim 1 , wherein a sidewall of said semiconductor fin and a sidewall of said conductive strap structure are within a same vertical plane.
5. The semiconductor structure of claim 1 , wherein a top surface of said semiconductor fin is coplanar with a top surface of said upper portion of said conductive strap structure.
6. The semiconductor structure of claim 1 , further comprising a dielectric fin portion overlying, and in contact with, a top surface of said semiconductor fin and a top surface of said upper portion of said conductive strap structure.
7. The semiconductor structure of claim 6 , wherein said topmost surfaces of said deep trench capacitor is located between a top surface of a buried insulator layer in said substrate and a bottom surface of said buried insulator layer, and wherein said second portion of said upper portion of said conductive strap structure contacts a portion of a sidewall of said insulator layer, and said dielectric cap contacts a remaining portion of said sidewall of said buried insulator layer.
8. The semiconductor structure of claim 1 , wherein said semiconductor fin and said first portion of said upper portion of said conductive strap structure have a same width.
9. A semiconductor structure comprising:
a semiconductor fin located on a substrate;
a deep trench capacitor embedded in said substrate;
a conductive strap structure overlying said deep trench capacitor, wherein said conductive strap structure comprises a lower portion vertically contacting topmost surfaces of said deep trench capacitor and an upper portion adjoined a portion of said lower portion, said upper portion having a first portion laterally contacting said semiconductor fin and a second portion underlying said first portion contacting a portion of said lower portion;
a dielectric cap embedded in said substrate, said dielectric cap vertically contacting another portion of said lower portion of said conductive strap structure and laterally surrounding said second portion of said upper portion of said conductive strap structure; and
a dielectric fin portion overlying, and in contact with, a top surface of said semiconductor fin and a top surface of said upper portion of said conductive strap structure.
10. A semiconductor structure comprising:
a semiconductor fin located on a substrate;
a deep trench capacitor embedded in said substrate;
a conductive strap structure overlying said deep trench capacitor, wherein said conductive strap structure comprises a lower portion vertically contacting topmost surfaces of said deep trench capacitor and an upper portion adjoined a portion of said lower portion, said upper portion having a first portion laterally contacting said semiconductor fin and a second portion underlying said first portion contacting a portion of said lower portion; and
a dielectric cap embedded in said substrate, said dielectric cap vertically contacting another portion of said lower portion of said conductive strap structure and laterally surrounding said second portion of said upper portion of said conductive strap structure,
wherein said semiconductor fin and said first portion of said upper portion of said conductive strap structure have a same width.