Method for avoiding IL regrown in a HKMG process
The present disclosure addresses and solves the current problem of oxygen accumulation in IL after an HKMG stack is formed. A fabrication method is provided for fabricating high-k/metal gate semiconductor device by forming at least one Titanium (Ti) layer between multiple HK layers. A high-k/metal gate semiconductor device including at least one TiO2 layer between multiple HK layers is also provided.
1. A semiconductor device comprising:
a substrate comprising silicon material; and
a gate electrode stack formed on the substrate, wherein the gate electrode stack comprising:
an interfacial layer formed on an upper surface of the substrate;
a first high-k dielectric layer formed on the interfacial layer;
a first titanium (Ti) only layer formed on the first high-k dielectric layer;
a second high-k dielectric layer formed on the first titanium only layer such that the first titanium only layer is not oxidized by a deposition process before the second high-k dielectric layer is formed on the first titanium only layer; and wherein the first titanium only layer is oxidized by oxygen from or through the first and the second high-k dielectric layer;
a third high-k dielectric layer formed on the second high-k dielectric layer;
a second titanium (Ti) only layer formed on the third high-k dielectric layer; and
a fourth high-k dielectric layer formed on the second titanium only layer such that the second titanium only layer is not oxidized by a deposition process before the fourth high-k dielectric layer is formed on the second titanium only layer; and wherein the second titanium only layer is oxidized by oxygen from or through the third and the fourth high-k dielectric layers.
2. The semiconductor device of claim 1 , wherein the gate electrode stack is formed using a high-k metal-gate gate-first process.
3. The semiconductor device of claim 1 , wherein the gate electrode stack is formed using a high-k metal-gate gate-last process.
4. The semiconductor device of claim 1 , wherein the first high-k dielectric layer is characterized by a thickness less than 1 nm.
5. The semiconductor device of claim 1 , wherein the second high-k dielectric layer is characterized by a thickness less than 1 nm.
6. The semiconductor device of claim 1 , wherein the second high-k dielectric layer is characterized by a thickness less than a thickness of the first high-k dielectric layer.
7. The semiconductor device of claim 1 , wherein the first and second high-k dielectric layers are characterized by a combined thickness less than 2 nm.
8. The semiconductor device of claim 1 , wherein the gate electrode stack further comprising at least one more composite structure, wherein the composite structure is formed by below method:
forming a new first high-k dielectric layer on previous high-k dielectric layer;
forming a new titanium (Ti) only layer on the new first high-k dielectric layer; and
forming a new second high-k dielectric layer on the new titanium only layer such that the new titanium only layer is not oxidized by a deposition process before the new second high-k dielectric layer is formed on the new titanium only layer; and wherein the new titanium only layer is oxidized by oxygen from or through the new first and the new second high-k dielectric layers.
9. The semiconductor device of claim 8 , wherein total thickness of all high-k dielectric layers is less than 2 nm.
10. The semiconductor device of claim 8 , wherein total thickness of all oxidized titanium only layers is less than 0.5 nm.
11. A method for fabricating a high-k metal-gate, the method comprising:
forming a substrate comprising silicon material; and
forming a gate electrode stack on the substrate, wherein forming the gate electrode stack comprising:
forming an interfacial layer on an upper surface of the substrate;
forming a first high-k dielectric layer on the interfacial layer;
forming a first titanium only layer on the first high-k dielectric layer without oxidizing the first titanium only layer;
forming a second high dielectric layer on the first titanium only layer such that the first titanium only layer is not oxidized by a deposition process before the second high-k dielectric layer is formed on the first titanium only layer; and wherein the first titanium only layer is oxidized by oxygen from or through the first and the second high-k dielectric layers;
forming a third high-k dielectric layer on the second high-k dielectric layer;
forming a second titanium (Ti) only layer on the third high-k dielectric layer; and
forming a fourth high-k dielectric layer on the second titanium only layer such that the second titanium only layer is not oxidized by a deposition process before the fourth high-k dielectric layer is formed on the second titanium only layer; and wherein the second titanium only layer is oxidized by oxygen from or through the third and the fourth high-k dielectric layers.
12. The method of claim 11 , wherein the gate electrode stack is formed using a high-k metal-gate gate-first process.
13. The method of claim 11 , wherein the gate electrode stack is formed using a high-k metal-gate gate-last process.
14. The method of claim 11 , wherein the first high-k dielectric layer is characterized by a thickness less than 1 nm.
15. The method of claim 11 wherein the second high-k dielectric layer is characterized by a thickness less than 1 nm.
16. The method of claim 11 , wherein the second high-k dielectric layer is characterized by a thickness less than a thickness of the first high-k dielectric layer.
17. The method of claim 11 , wherein the first and second high-k dielectric layers are characterized by a combined thickness less than 2 nm.
18. The method of claim 11 , wherein forming the gate electrode stack further comprising forming at least one more composite structure, wherein the composite structure is formed by below method:
forming a new first high-k dielectric layer on previous high-k dielectric layer;
forming a new titanium (Ti) only layer on the new first high-k dielectric layer; and
forming a new second high-k dielectric layer on the new titanium only layer such that the new titanium only layer is not oxidized by a deposition process before the new second high-k dielectric layer is formed on the new titanium only layer; and wherein the new titanium only layer is oxidized by oxygen from or through the new first and the new second high-k dielectric layers.
19. The method of claim 18 , wherein total thickness of all high-k dielectric layers is less than 2 nm.
20. The method of claim 18 , wherein total thickness of all oxidized titanium only layers is less than 0.5 nm.