Work function adjustment in a high-k gate electrode structure after transistor fabrication by using lanthanum
First Claim
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1. A method, comprising:
- forming a first gate electrode structure of a first transistor above a semiconductor layer, said first gate electrode structure comprising a first placeholder electrode material formed above a high-k gate insulation layer;
forming a second gate electrode structure of a second transistor above the semiconductor layer, said second gate electrode structure comprising a second placeholder electrode material formed above a high-k insulation layer, wherein the second transistor has a different conductivity type as compared to said first transistor;
forming drain and source regions of said first and second transistors;
removing said first placeholder electrode material concurrently with removing said second placeholder electrode material;
forming a metal layer above said first and second gate electrode structures and selectivity removing the metal layer from above said first gate electrode structure so as to adjust a work function of said second gate electrode structure;
forming a lanthanum-containing material layer above said first and second transistors after forming and selectively removing said metal layer; and
forming a metal-containing electrode material on said lanthanum-containing material layer.
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Abstract
The work function of a high-k gate electrode structure may be adjusted in a late manufacturing stage on the basis of a lanthanum species in an N-channel transistor, thereby obtaining the desired high work function in combination with a typical conductive barrier material, such as titanium nitride. For this purpose, in some illustrative embodiments, the lanthanum species may be formed directly on the previously provided metal-containing electrode material, while an efficient barrier material may be provided in the P-channel transistor, thereby avoiding undue interaction of the lanthanum species in the P-channel transistor.
9 Citations
19 Claims
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1. A method, comprising:
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forming a first gate electrode structure of a first transistor above a semiconductor layer, said first gate electrode structure comprising a first placeholder electrode material formed above a high-k gate insulation layer; forming a second gate electrode structure of a second transistor above the semiconductor layer, said second gate electrode structure comprising a second placeholder electrode material formed above a high-k insulation layer, wherein the second transistor has a different conductivity type as compared to said first transistor; forming drain and source regions of said first and second transistors; removing said first placeholder electrode material concurrently with removing said second placeholder electrode material; forming a metal layer above said first and second gate electrode structures and selectivity removing the metal layer from above said first gate electrode structure so as to adjust a work function of said second gate electrode structure; forming a lanthanum-containing material layer above said first and second transistors after forming and selectively removing said metal layer; and forming a metal-containing electrode material on said lanthanum-containing material layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method, comprising:
- removing a placeholder material of a first gate electrode structure of a first transistor concurrently with removing a placeholder material of of a second gate electrode structure of a second transistor so as to expose a metal-containing material formed on a high-k gate insulation layer of said first and second gate electrode structures, said first and second transistors having different conductivity types;
forming a work function adjusting material on said metal-containing material in said first gate electrode structure and on a conductive barrier material in said second gate electrode structure;
forming a first metal layer on said work function adjusting material; and
forming a second metal layer on said metal-containing material of said second gate electrode structure, said second metal layer defining a work function of said second gate electrode structure in combination with said metal-containing material. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
- removing a placeholder material of a first gate electrode structure of a first transistor concurrently with removing a placeholder material of of a second gate electrode structure of a second transistor so as to expose a metal-containing material formed on a high-k gate insulation layer of said first and second gate electrode structures, said first and second transistors having different conductivity types;
Specification