Preventing strained fin relaxation by sealing fin ends
A semiconductor structure includes a first strained fin portion and a second strained fin portion, a pair of inactive inner gate structures upon respective strained fin portions, and spacers upon outer sidewalls surfaces of the inactive inner gate structures, upon the inner sidewall surfaces of the inactive inner gate structures, and upon the first strained fin portion and the second strained fin portion end surfaces. The first strained fin portion and the second strained fin portion end surfaces are coplanar with respective inner sidewall surfaces of the inactive inner gate structures. The spacer formed upon the end surfaces limits relaxation of the first strained fin portion and the second strained fin portion and limits shorting between the first strained fin portion and the second strained fin portion.
1. A semiconductor structure fabrication method comprising:
forming a strained fin from a strained multilayered substrate;
forming a pair of inactive inner gate structures upon the strained multilayered substrate and upon the strained fin;
separating the strained fin into fin portions by removing strained fin material between the pair of inactive inner gate structures, the separation of the strained fin exposing fin portion ends coplanar with respective inner sidewall surfaces of the pair of inactive inner gate structures; and
forming spacers upon outer sidewalls surfaces of the inactive inner gate structures, upon the inner sidewall surfaces of the inactive inner gate structures, and upon the exposed fin portion ends.
2. The semiconductor structure fabrication method of claim 1 , wherein the spacer formed upon the exposed fin portion ends limits strain relaxation of the fin portions.
3. The semiconductor structure fabrication method of claim 1 , wherein the spacer formed upon the exposed fin portion ends limits shorting between the fin portions.
4. The semiconductor structure fabrication method of claim 1 , further comprising:
forming one or more outer gate structures upon the strained multilayered substrate and upon the strained fin outside the pair of inactive inner gate structures, and;
forming spacers upon sidewall surfaces of the one or more outer gate structures.
5. The semiconductor structure fabrication method of claim 1 , wherein the pair of the inactive inner gate structures are electrically inactive.
6. The semiconductor structure fabrication method of claim 4 , wherein the one or more outer gate structures are electrically active.
7. The semiconductor structure fabrication method of claim 1 , wherein the fin portion ends are tucked in from respective inner sidewall surfaces of the inactive inner gate structures, and wherein the spacer formed upon the exposed fin portion ends prevent epi nodule formation.
8. The semiconductor structure fabrication method of claim 1 , further comprising:
forming a fin-cut mask layer upon the strained multilayered substrate, upon the strained fin, and upon the pair of inactive inner gate structures;
forming a self-aligned trench within the fin-cut mask layer between the pair of inactive inner gate structures, the self-aligned trench separating the strained fin into fin portions.
9. The semiconductor structure fabrication method of claim 1 , wherein the strained multilayered substrate is a SiGe on insulator (SGOI) substrate.