Electronic device comprising a gate electrode including a metal-containing layer having one or more impurities
View Patent ↗One or more impurities may be incorporated within a metal-containing layer of a metal-containing gate electrode to modify the work function of the metal-containing gate electrode of a transistor can affect the threshold voltage of the transistor. In one embodiment, the impurity can be used in a p-channel transistor to allow the work function of a metal-containing gate electrode to be closer to the valence band for silicon. In another embodiment, the impurity can be used in an n-channel transistor to allow the work function of a metal-containing gate electrode to be closer to the conduction band for silicon. In a particular embodiment, a boron-containing species is implanted into a metal-containing layer within the metal-containing gate electrode within a p-channel transistor, so that the metal-containing gate electrode has a work function closer to the valence band for silicon as compared to the metal-containing gate electrode without the boron-containing species.
1. An electronic device comprising:
a substrate including a first portion and a second portion;
a gate dielectric layer overlying the first portion and the second portion of the substrate;
a first gate electrode overlying the gate dielectric layer and the first portion of the substrate, wherein:
the first gate electrode includes a first portion of a first layer, a first portion of a second layer, and a first portion of a third layer, wherein the second layer lies between the first layer and the third layer;
the first portion of the first layer lies immediately adjacent to the gate dielectric layer; and
the first layer comprises a first element that is a metallic element and an impurity that includes a second element within Group 2 or 13 of the Periodic Table;
a first source/drain region overlying the first portion of the substrate, wherein a first transistor includes the first source/drain and the first gate electrode;
a second gate electrode overlying the gate dielectric layer and the second portion of the substrate, wherein:
the second gate electrode includes a second portion of the second layer and a second portion of the third layer; and
the second portion of the second layer lies immediately adjacent to the gate dielectric layer; and
a second source/drain region overlying the second portion of the substrate, wherein a second transistor includes the second source/drain and the second gate electrode.
2. The electronic device of claim 1 , wherein the impurity comprises a boron-containing species.
3. The electronic device of claim 1 , wherein the second gate electrode does not include the first layer.
4. The electronic device of claim 1 , wherein:
the first transistor is a PMOS transistor;
the first layer substantially determines a work function of the PMOS transistor;
the second transistor is an NMOS transistor; and
the second layer substantially determines a work function of the NMOS transistor.
5. An electronic device comprising:
a substrate including a first portion and a second portion;
a first transistor overlying the first portion of the substrate, wherein the first transistor includes:
a first channel region;
a first gate dielectric layer overlying the first channel region; and
a first gate electrode overlying the first gate dielectric layer, wherein:
the first gate electrode includes a first layer lying immediately adjacent to the first gate dielectric layer; and
the first layer includes:
a first element that is a first transition metal element; and
a second element that is an element within Group 2 or 13 of the Periodic Table; and
a second transistor overlying the second portion of the substrate, wherein the second transistor includes:
a second channel region;
a second gate dielectric layer overlying the second channel region; and
a second gate electrode overlying the second gate dielectric layer, wherein:
the second gate electrode includes a second layer; and
the second layer includes a third element that is a second transition metal element, and the second layer does not include boron.
6. The electronic device of claim 5 , wherein the second element is boron.
7. The electronic device of claim 5 , wherein the first transition metal element is different from the second transition metal element.
8. The electronic device of claim 7 , wherein the first gate dielectric layer and the second gate dielectric layer are different portions of a same gate dielectric layer.
9. The electronic device of claim 5 , wherein each of the first gate dielectric layer and the second gate dielectric layer includes hafnium, zirconium, or any combination thereof.
10. The electronic device of claim 5 , wherein the first layer comprises a fourth element other than silicon, wherein the fourth element is different from the first and second elements.
11. The electronic device of claim 5 , wherein the first transistor is a PMOS transistor, and
the second transistor is an NMOS transistor.
12. The electronic device of claim 11 , wherein the first layer comprises TiN, and
the third layer comprises TaSiN.
13. The electronic device of claim 5 , wherein the first gate electrode does not include the second layer, and the second gate electrode does not include the first layer.
14. An electronic device comprising:
a substrate including a first portion and a second portion;
a gate dielectric layer overlying the first portion and the second portion of the substrate;
a first transistor overlying the first portion of the substrate and comprising a first gate electrode and a first source/drain region, wherein:
the first gate electrode overlies the gate dielectric layer;
the first gate electrode includes a first layer and a second layer;
the first layer includes a first metallic element and substantially determines a work function for the first electrode; and
the first source/drain region lies adjacent to the first gate electrode; and
a second transistor overlying the second portion of the substrate and comprising a second gate electrode and a second source/drain region, wherein:
the second gate electrode overlies the gate dielectric layer;
the second gate electrode includes the second layer and a third layer;
the third layer includes a second metallic element and a boron-containing species, and the third layer substantially determines a work function of the second gate electrode; and
the second source/drain region lies adjacent to the second gate electrode, wherein:
the first metallic element is different from the second metallic element; and
the first layer does not include the second metallic element. or the third layer does not include the first metallic element.
15. The electronic device of claim 14 , wherein the second layer comprises an elemental transition metal, a transition metal nitride, a transition metal silicon nitride, or any combination thereof.
16. The electronic device of claim 14 , wherein:
the first transistor is a NMOS transistor;
the first layer lies immediately adjacent to the gate dielectric layer;
the second transistor is a PMOS transistor; and
the third layer lies immediately adjacent to the gate dielectric layer.
17. The electronic device of claim 16 , wherein first gate electrode does not include the third layer, and the second gate electrode does not include the first layer.
18. The electronic device of claim 16 , wherein first gate electrode includes the third layer, and the second gate electrode does not include the first layer,
19. The electronic device of claim 16 , wherein the first gate electrode includes a different number of layers as compared to the second gate electrode,
20. The electronic device of claim 14 , wherein:
the first metallic element includes Ta, Hf, Nb, or NiSi; and
the second metallic element includes Ti, Mo, Ru, Ir, or Mo.