Stress enhanced MOS circuits
View Patent ↗A stress enhanced MOS circuit is provided. The stress enhanced MOS circuit comprises a semiconductor substrate and a gate insulator overlying the semiconductor substrate. A gate electrode overlies the gate insulator; the gate electrode has side walls and comprising a layer of polycrystalline silicon having a first thickness in contact with the gate insulator and a layer of electrically conductive stressed material having a second thickness greater than the first thickness overlying the layer of polycrystalline silicon. A stress liner overlies the side walls of the gate electrode.
1. A stress enhanced MOS circuit, comprising:
a semiconductor substrate;
a gate insulator overlying the semiconductor substrate;
a gate electrode overlying the gate insulator, the gate electrode having side walls and comprising a layer of polycrystalline silicon having a first thickness in contact with the gate insulator and a layer of electrically conductive stressed material having a second thickness greater than the first thickness, the layer of electrically conductive stressed material overlying and contacting the layer of polycrystalline silicon; and
a stress liner layer overlying the side walls.
2. The MOS circuit of claim 1 wherein the second thickness is at least five times the first thickness.
3. The MOS circuit of claim 1 wherein the electrically conductive stressed material comprises titanium nitride.
4. The MOS circuit of claim 3 wherein the stress liner layer comprises silicon nitride.
5. The MOS circuit of claim 1 wherein the electrically conductive stressed material comprises a tensile stressed material.
6. The MOS circuit of claim 5 wherein the stress liner layer comprises a compressive stressed material.
7. The MOS circuit of claim 5 wherein the tensile stressed material has a tensile stress of at least approximately 2.0 GPa.
8. The MOS circuit of claim 3 wherein the titanium nitride has a compressive stress greater than approximately −2.5 GPa.
9. The MOS circuit of claim 8 wherein the titanium nitride has a compressive stress of approximately −10 GPa.
10. The MOS circuit of claim 1 wherein the electrically conductive stressed material comprises compressive stressed material.
11. The MOS circuit of claim 10 wherein the stress liner layer comprises a tensile stressed material.
12. The MOS circuit of claim 4 wherein the silicon nitride has a tensile stress of about 1.2 GPa.