Integrated tensile strained silicon NFET and compressive strained silicon-germanium PFET implemented in FinFET technology
A tensile strained silicon layer is patterned to form a first group of fins in a first substrate area and a second group of fins in a second substrate area. The second group of fins is covered with a tensile strained material, and an anneal is performed to relax the tensile strained silicon semiconductor material in the second group of fins and produce relaxed silicon semiconductor fins in the second area. The first group of fins is covered with a mask, and silicon-germanium material is provided on the relaxed silicon semiconductor fins. Germanium from the silicon germanium material is then driven into the relaxed silicon semiconductor fins to produce compressive strained silicon-germanium semiconductor fins in the second substrate area (from which p-channel finFET devices are formed). The mask is removed to reveal tensile strained silicon semiconductor fins in the first substrate area (from which n-channel finFET devices are formed).
1. A method, comprising:
depositing a hard mask on a tensile strained semiconductor layer of a substrate;
patterning said hard mask and tensile strained semiconductor layer into a plurality of fins;
forming and patterning a tensile strained material so that the tensile strained material covers the plurality of fins;
performing an anneal which relaxes the tensile strained semiconductor material in the plurality of fins resulting in a relatively lower tensile strain in the plurality of fins;
forming a semiconductor material on the plurality of fins, the semiconductor material including germanium; and
driving germanium from the semiconductor material into the plurality of fins to produce compressive strained semiconductor fins.
2. The method of claim 1 , further comprising using the compressive strained semiconductor fins to produce finFET transistors.
3. The method of claim 2 , wherein the finFET transistors are p-type transistors.
4. The method of claim 1 , wherein the tensile strained material is tensile strained silicon nitride.
5. The method of claim 1 , wherein forming the semiconductor material comprises epitaxially growing semiconductor material including germanium on exposed semiconductor surfaces of the plurality of fins.
6. The method of claim 1 , wherein forming the semiconductor material comprises depositing amorphous semiconductor material including germanium On exposed semiconductor surfaces of the plurality of fins.
7. The method of claim 1 , further comprising producing finFET transistors using the compressive strained semiconductor fins by:
forming a dummy gate extending over the compressive strained semiconductor fins, said dummy gate including a polysilicon material;
forming sidewall spacers on the dummy gate; and
replacing the polysilicon material of the dummy gate with a replacement metal gate structure.
8. The method of claim 1 , wherein the substrate is a silicon on insulator type substrate.
9. The method of claim 7 , wherein forming sidewall spacers comprises:
forming an oxide sidewall spacer; and
forming a nitride sidewall spacer on the oxide sidewall spacer.