What is claimed is:
1. A method for making a semiconductor device comprising:
forming a dielectric layer on a substrate;
forming an impurity containing metal layer on the dielectric layer; and then
forming a metal gate electrode from the impurity containing metal layer.
2. The method of claim 1 wherein the dielectric layer comprises a high-k gate dielectric layer.
3. The method of claim 2 wherein the high-k gate dielectric layer is formed by atomic layer chemical vapor deposition, and comprises a material selected from the group consisting of hafnium oxide, hafnium silicon oxide, lanthanum oxide, zirconium oxide, zirconium silicon oxide, titanium oxide, tantalum oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate.
4. The method of claim 1 wherein the impurity containing metal layer can tolerate temperatures that exceed about 900 C.
5. The method of claim 2 wherein the impurity containing metal layer comprises a material that is selected from the group consisting of tungsten, platinum, ruthenium, palladium, molybdenum and niobium, and their alloys, metal carbides, metal nitrides, and conductive metal oxides.
6. The method of claim 5 wherein the impurity containing metal layer comprises a material that is selected from the group consisting of titanium carbide, zirconium carbide, tantalum carbide, tungsten carbide, titanium nitride, tantalum nitride, and ruthenium oxide.
7. The method of claim 1 wherein the impurity containing metal layer is formed by:
forming a metal layer that has a workfunction of between about 4.3 eV and about 4.9 eV; and then
adding to the metal layer a sufficient amount of an element to shift the metal layer’s workfunction by at least about 0.1 eV.
8. The method of claim 7 wherein the metal gate electrode will serve as the gate electrode for an NMOS transistor, and wherein the element has an electronegativity value that is less than about 1.7.
9. The method of claim 8 wherein the element is selected from the group consisting of a lanthanide metal, an alkali metal, an alkaline earth metal, scandium, zirconium, hafnium, aluminum, titanium, tantalum, niobium, and tungsten.
10. The method of claim 9 wherein the element is aluminum.
11. The method of claim 7 wherein the metal gate electrode will serve as the gate electrode for a PMOS transistor, and wherein the element has an electronegativity value that is greater than about 2.8.
12. The method of claim 11 wherein the element is selected from the group consisting of nitrogen, chlorine, oxygen, fluorine, and bromine.
13. The method of claim 12 wherein the element is chlorine.
14. The method of claim 7 wherein the element is added to the metal layer until it comprises between about 3 and about 50 atomic percent of the impurity containing metal layer.
15. A method for making a CMOS transistor comprising:
forming a high-k gate dielectric layer on a substrate; and
forming an impurity containing metal layer on the high-k gate dielectric layer;
wherein a first portion of the impurity containing metal layer includes a sufficient amount of a first element to lower the metal layer’s workfunction and wherein a second portion of the impurity containing metal layer includes a sufficient amount of a second element to raise the metal layer’s workfunction.
16. The method of claim 15 further comprising forming a gate electrode for an NMOS transistor from the first portion of the impurity containing metal layer, and forming a gate electrode for a PMOS transistor from the second portion of the impurity containing metal layer, and wherein the first element has an electronegativity value that is less than about 1.7, and the second element has an electronegativity value that is greater than about 2.8.
17. The method of claim 15 wherein the impurity containing metal layer is formed by:
forming a metal layer that has a workfunction of between about 4.3 eV and about 4.9 eV; and then
adding to a first portion of the metal layer a sufficient amount of a first element to lower the metal layer’s workfunction to between about 4.0 eV and about 4.2 eV, and
adding to a second portion of the metal layer a sufficient amount of a second element to raise the metal layer’s workfunction to between about 5.0 eV and about 5.2 eV.
18. The method of claim 17 wherein the first element is added to the first portion of the metal layer while the second portion of the metal layer is masked, and the second element is added to the second portion of the metal layer while the first portion of the metal layer is masked.
19. The method of claim 18 wherein the first element is selected from the group consisting of a lanthanide metal, scandium, zirconium, hafnium, aluminum, titanium, tantalum, niobium, and tungsten, and the second element is selected from the group consisting of nitrogen, chlorine, oxygen, fluorine, and bromine.
20. The method of claim 19 wherein the first element is added to the metal layer until it comprises between about 3 and about 50 atomic percent of the first portion of the impurity containing metal layer, and the second element is added to the metal layer until it comprises between about 3 and about 50 atomic percent of the second portion of the impurity containing metal layer.
21. A semiconductor device comprising:
a dielectric layer formed on a substrate; and
a metal gate electrode formed on the dielectric layer;
wherein the metal gate electrode includes a sufficient amount of an impurity to shift the metal gate electrode’s workfunction by at least about 0.1 eV.
22. The semiconductor device of claim 21 wherein the dielectric layer comprises a high-k gate dielectric layer.
23. The semiconductor device of claim 22 wherein the high-k gate dielectric layer is formed by atomic layer chemical vapor deposition, and comprises a material selected from the group consisting of hafnium oxide, hafnium silicon oxide, lanthanum oxide, zirconium oxide, zirconium silicon oxide, titanium oxide, tantalum oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate.
24. The semiconductor device of claim 21 wherein the metal gate electrode serves as the gate electrode for an NMOS transistor, and wherein the impurity is an element that has an electronegativity value that is less than about 1.7.
25. The semiconductor device of claim 24 wherein the element is selected from the group consisting of a lanthanide metal, an alkali metal, an alkaline earth metal, scandium, zirconium, hafnium, aluminum, titanium, tantalum, niobium, and tungsten.
26. The semiconductor device of claim 21 wherein the metal gate electrode serves as the gate electrode for a PMOS transistor, and wherein the impurity is an element that has an electronegativity that is greater than about 2.8.
27. The semiconductor device of claim 26 wherein the element is selected from the group consisting of nitrogen, chlorine, oxygen, fluorine, and bromine.
28. The semiconductor device of claim 21 wherein the impurity is present in the metal gate electrode at a concentration of between about 3 and about 50 atomic percent.
29. The semiconductor device of claim 21 wherein the metal gate electrode is a first metal gate electrode and further comprising a second metal gate electrode; and wherein the first metal gate electrode includes a sufficient amount of a first element to lower the workfunction of the first metal gate electrode by at least about 0.1 eV, and the second metal gate electrode includes a sufficient amount of a second element to raise the workfunction of the second metal gate electrode by at least about 0.1 eV.
30. The semiconductor device of claim 29 wherein:
the first metal gate electrode serves as the gate electrode for an NMOS transistor;
the first element has an electronegativity value that is less than about 1.7, is selected from the group consisting of a lanthanide, scandium, zirconium, hafnium, aluminum, titanium, tantalum, niobium, and tungsten, and is present in the first metal gate electrode at a concentration of between about 3 and about 50 atomic percent;
the second metal gate electrode serves as the gate electrode for a PMOS transistor; and
the second element has an electronegativity value that is greater than about 2.8, is selected from the group consisting of nitrogen, chlorine, oxygen, fluorine, and bromine, and is present in the second metal gate electrode at a concentration of between about 3 and about 50 atomic percent.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for oxidative treatment of gaseous pollutants in a process gas stream, comprising the steps of:
conducting said gas stream into a thermal reactor via a process gas inlet, wherein said thermal reactor comprises heating elements, and wherein said process gas inlet comprises a conduit terminating with a portion of said conduit within said reactor wherein said portion of said conduit is located within a tube which projects beyond the end of said conduit to define a chamber within said tube, said tube having an open end communicating with the interior of said reactor; and
introducing other gases into said conduit via an independent inlet communicatively connected to said conduit, said independent inlet positioned along said conduit before said conduit terminates in said tube, said thermal reactor comprising a central chamber comprising said heating elements, an entry end and an exit end of said chamber, a side inlet communicating with an exterior air space defined by an exterior wall of the reactor and said heating elements, an interior air space communicating with said exterior air space, said interior air space defined by an interior wall of the reactor and said heating elements, and an orifice in said interior wall for introducing air from said interior space into said central chamber.
2. The method of claim 1, wherein said conduit is curved.
3. The method of claim 1, wherein said conduit and independent inlet are concentrically located.
4. The method of claim 1, wherein a plurality of gas streams are introduced to said reactor via a plurality of process gas inlets.
5. The method of claim 1, further comprising the step of:
flowing the gas stream after treatment in said thermal reactor to a particle removal chamber.
6. The method of claim 5, wherein said particle removal chamber comprises:
a packed bed;
at least one liquid inlet positioned at the top of said chamber to provide a washing liquid to an intermittent sprayer; and
a continuous sprayer, wherein the packed bed is for trapping and condensing particles and said gas stream is upwardly flowed through said bed against downwardly flowing liquid; and
an air inlet positioned below said liquid inlets to provide flowing air onto the upper portion of said bed to cool an upper portion of said bed to promote condensation and particle growth within said bed.
7. The method of claim 1, further comprising the step of:
flowing the gas stream after treatment in said thermal reactor to a scrubber for removing chemical pollutants.
8. The method of claim 7, wherein said scrubber comprises:
an inlet for introducing said gas stream into a scrubbing chamber of said scrubber via an inlet, wherein said scrubbing chamber contains coated packing in at least two vertically separated beds, said coating being adapted to entrap or react with said pollutants.
9. The method of claim 7, further comprising the steps of:
monitoring the amount of said pollutants being removed from said stream by said scrubber;
controlling selective introduction of a regenerative coating composition onto each of said beds to regenerate said coating on said packing.
10. The method of claim 9, wherein said step of monitoring is performed by a detector that measures the concentration of a pollutant in the gas exiting said scrubber.
11. The method of claim 9, further comprising the step of:
introducing said coating composition to said beds at predetermined time intervals.
12. A method of treating gaseous pollutants in a gas stream, comprising the steps of:
oxidatively treating a gas stream within a thermal reactor with other gases introduced into said thermal reactor, said thermal reactor comprising a central chamber comprising heating elements, an entry end and an exit end of said central chamber, a side inlet communicating with an exterior air space defined by an exterior wall of the reactor and said heating elements, an interior air space communicating with said exterior air space, said interior air space defined by an interior wall of the reactor and said heating elements, and an orifice in said interior wail for introducing air from said interior space into said central chamber;
introducing said oxidatively treated gas stream into a scrubber for removing chemical pollutants in said gas stream;
monitoring the amount of said pollutants being removed from said stream by said scrubber; and
selectively introducing a regenerative coating composition onto each of at least two vertically separated beds.