MOSFET gate and source/drain contact metallization
A MOSFET is described incorporating a common metal process to make contact to the source, drain and the metal gate respectively which may be formed concurrently with the same metal or metals.
1. A method for forming a field effect transistor comprising:
selecting a Si containing substrate having a source, drain and channel regions, said channel region having a sacrificial gate dielectric, sacrificial Si gate electrode and sidewall spacers thereover, then
forming a metal silicide only in said source and drain regions,
forming a first dielectric layer thicker than and over said sacrificial Si gate electrode,
planarizing said first dielectric layer down to said sacrificial Si gate electrode,
removing said sacrificial gate dielectric and said sacrificial Si gate electrode, then
forming a second dielectric layer on said channel region, then
forming a metal gate layer over said second dielectric layer, then
forming openings in said first and second dielectric layers to said source and drain regions,
forming a first metal liner layer over said metal silicide in said source and drain regions and over said metal gate layer, and over sidewalls of said openings in said first and second dielectric layers,
forming a second metal layer over said first metal liner layer having a thickness to fill said openings, and
planarizing said first metal layer and said second metal layer down to said first dielectric layer.
2. The method of claim 1 wherein said forming a first metal liner layer includes forming a layer selected from the group consisting of tantalum, titanium, titanium nitride, tantalum nitride, titanium silicon nitride, ruthenium, ruthenium oxide, ruthenium phosphorus, hafnium, zirconium, aluminum, manganese, copper manganese, iridium, copper iridium, cobalt, cobalt tungsten, cobalt tungsten phosphorus, tungsten, lanthanum, lutetium, transition metal elements, rare earth elements, a metal carbide, a conductive metal oxide and combinations thereof.
3. The method of claim 1 wherein said forming a second metal layer includes forming a layer selected from the group consisting of copper, ruthenium, palladium, platinum, cobalt, nickel, ruthenium oxide, tungsten, aluminum, manganese, cobalt tungsten, cobalt tungsten phosphorus, titanium, tantalum, hafnium zirconium, transition metal elements, rare earth elements, a metal carbide, carbon nano tubes, a conductive metal oxide and combinations thereof.
4. The method of claim 1 wherein said forming a second dielectric layer includes forming a high K dielectric layer.
5. The method of claim 1 wherein said forming a metal gate layer includes forming a metal gate layer over said second dielectric layer over said channel region.
6. The method of claim 1 wherein said forming openings includes forming openings in said metal gate layer and said first and second dielectric layers.
7. The method of claim 1 wherein said forming a first metal liner layer includes forming a first metal liner layer over said metal gate layer over said channel region and over said sidewall spacers.
8. The method of claim 1 wherein said forming a second metal includes forming a second metal over said first metal liner layer having a thickness to fill an opening over said first metal liner layer over said channel region left by removing said sacrificial gate dielectric and said sacrificial Si gate electrode.
9. A method for forming a field effect transistor comprising:
selecting a Si containing substrate having a source, drain and channel regions, said channel region having a sacrificial gate dielectric, sacrificial Si gate electrode and sidewall spacers thereover, then
forming a metal silicide in said source and drain regions,
forming a first dielectric layer thicker than and over said sacrificial Si gate electrode,
planarizing said first dielectric layer down to said sacrificial Si gate electrode,
removing said sacrificial gate dielectric and said sacrificial Si gate electrode, then
forming a second dielectric layer on said channel region, then
forming a metal gate layer over said second dielectric layer, then
forming openings in said first and second dielectric layers to said source and drain regions,
forming a first metal liner layer over said metal silicide in said source and drain regions and over said metal gate layer, and over sidewalls of said openings in said first and second dielectric layers,
forming a second metal layer over said first metal liner layer having a thickness to fill said openings, and
planarizing said first metal layer and said second metal layer down to said first dielectric layer.
10. The method of claim 9 wherein said forming a first metal liner layer includes forming a layer selected from the group consisting of tantalum, titanium, titanium nitride, tantalum nitride, titanium silicon nitride, ruthenium, ruthenium oxide, ruthenium phosphorus, hafnium, zirconium, aluminum, manganese, copper manganese, iridium, copper iridium, cobalt, cobalt tungsten, cobalt tungsten phosphorus, tungsten, lanthanum, lutetium, transition metal elements, rare earth elements, a metal carbide, a conductive metal oxide and combinations thereof.
11. The method of claim 9 wherein said forming a second metal layer includes forming a layer selected from the group consisting of copper, ruthenium, palladium, platinum, cobalt, nickel, ruthenium oxide, tungsten, aluminum, manganese, cobalt, cobalt tungsten, cobalt tungsten phosphorus, titanium, tantalum, hafnium zirconium, transition metal elements, rare earth elements, a metal carbide, carbon nano tubes, a conductive metal oxide and combinations thereof.
12. The method of claim 9 wherein said forming a second dielectric layer includes forming a high K dielectric layer.
13. The method of claim 9 wherein said forming a metal gate layer includes forming a metal gate layer over said second dielectric layer over said channel region.
14. The method of claim 9 wherein said forming openings includes forming openings in said metal gate layer and said first and second dielectric layers.
15. The method of claim 9 wherein said forming a first metal liner layer includes forming a first metal liner layer over said metal gate layer over said channel region and over said sidewall spacers.
16. The method of claim 9 wherein said forming a second metal includes forming a second metal over said first metal liner layer having a thickness to fill an opening over said first metal liner layer over said channel region left by removing said sacrificial gate dielectric and said sacrificial Si gate electrode.