Localized implant into active region for enhanced stress
View Patent ↗Methods for enhancing strain in an integrated circuit are provided. Embodiments of the invention include using a localized implant into an active region prior to a gate etch. In another embodiment, source/drain regions adjacent to the gates are recessed to allow the strain to expand to full potential. New source/drain regions are allowed to grow back to maximize stress in the active region.
1. A method comprising:
providing a semiconductor substrate including an active semiconductor region and a non-active semiconductor region;
depositing a first gate layer on the active semiconductor region and the non-active semiconductor region of the semiconductor substrate;
implanting a stress-inducing material into the first gate layer;
after said implanting a stress-inducing material, removing the first gate layer over the non-active region of the semiconductor substrate, the first gate layer implanted with the stress-inducing material remaining on the active semiconductor region of the semiconductor substrate;
after said removing the first gate layer over the non-active region, depositing a second gate layer on the first gate layer implanted with the stress inducing material; and
after depositing the second gate layer on the first gate layer implanted with the stress inducing material, annealing the semiconductor substrate to create stress in the active semiconductor region; and then
increasing stress in the active semiconductor region of the semiconductor substrate after the annealing by:
removing source/drain regions of the semiconductor substrate adjacent to the active semiconductor region to a depth of the active semiconductor region; and then,
re-growing source/drain regions adjacent to the active semiconductor region.
2. The method of claim 1 , further comprising forming the first gate layer and the second gate layer into a gate structure after the second gate layer depositing.
3. The method of claim 1 , further comprising forming the first gate layer and the second gate layer into a gate structure after the annealing.
4. The method of claim 3 , wherein the gate structure includes a spacer about the first gate layer and the second gate layer, and a cap above the second gate layer.
5. The method of claim 1 , wherein the implanting includes a dose in the range of approximately 2×10 20 to approximately 3×10 21 atoms/cm 3 .
6. The method of claim 1 , wherein the second gate layer is thicker than the first gate layer.