Methods of fabricating semiconductor devices
A method of fabricating a semiconductor device includes forming first and second gate dielectric layers on first and second regions of a semiconductor substrate, respectively, forming a first metal-containing layer on the first and second gate dielectric layers, performing a first annealing process with respect to the first metal-containing layer, removing the first metal-containing layer from the first region, forming a second metal-containing layer on an entire surface of the semiconductor substrate, performing a second annealing process with respect to the second metal-containing layer, forming a gate electrode layer on the second metal-containing layer, and partially removing the gate electrode layer, the second metal-containing layer, the first metal-containing layer, the first gate dielectric layer, and the second gate dielectric layer to form first and second gate patterns on the first and second regions, respectively.
1. A method of fabricating a semiconductor device, the method comprising:
forming a first gate dielectric layer and a second gate dielectric layer on a first region and a second region included in a semiconductor substrate, respectively;
forming a first metal-containing layer on the first and second gate dielectric layers;
performing a first annealing process with respect to the first metal-containing layer;
removing the first metal-containing layer from the first region;
forming a second metal-containing layer on an entire surface of the semiconductor substrate;
performing a second annealing process with respect to the second metal-containing layer;
forming a gate electrode layer on the second metal-containing layer;
partially removing the gate electrode layer, the second metal-containing layer, the first metal-containing layer, the first gate dielectric layer, and the second gate dielectric layer to form a first gate pattern and a second gate pattern on the first region and the second region, respectively; and
performing a third annealing process after the removing the first metal-containing layer from the first region and before the forming the second metal-containing layer.
2. The method of claim 1 , wherein at least one of the first and second gate dielectric layers comprises a high-k dielectric layer having a dielectric constant greater than a dielectric constant of a silicon oxide layer.
3. The method of claim 1 , wherein
the first annealing process includes supplying gas to reduce or oxidize the first metal-containing layer, and
the second annealing process includes supplying gas to reduce or oxidize the second metal-containing layer.
4. The method of claim 3 , wherein
the gas reducing the first and second metal-containing layers comprises at least one of hydrogen (H 2 ), nitrogen (N 2 ), and ammonia (NH 3 ), and
the gas oxidizing the first and second metal-containing layers comprises at least one of oxygen (O 2 ), ozone (O 3 ), nitrogen monoxide (NO), and nitrogen dioxide (NO 2 ).
5. The method of claim 1 , wherein
the first region is an NMOS transistor region,
the second region is a PMOS transistor region,
the first annealing process includes supplying at least one of nitrogen and oxygen, and
the second annealing process includes supplying ammonia.
6. The method of claim 5 , further comprising:
forming a mask pattern on the second metal-containing layer to cover the second region and to expose the first region before the performing a second annealing process.
7. The method of claim 1 , further comprising:
forming a third metal-containing layer on the semiconductor substrate; and
performing the third annealing process with respect to the third metal-containing layer before the forming a gate electrode layer,
wherein at least one of the first and second gate patterns further comprises the third metal-containing layer.
8. The method of claim 1 , further comprising:
forming a first dummy gate pattern in contact with the semiconductor substrate on the first region, a second dummy gate pattern in contact with the semiconductor substrate on the second region, and an interlayer dielectric layer in contact with sidewalls of the first and second dummy gate patterns; and
removing the first and second dummy gate patterns to form a first gate groove and a second gate groove each of which exposes the semiconductor substrate before the forming first and second gate dielectric layers,
wherein the forming first and second gate patterns comprises exposing a top surface of the interlayer dielectric layer by performing a planarization process with respect to the gate electrode layer, the second metal-containing layer, the first metal-containing layer, the first gate dielectric layer, and the second gate dielectric layer,
wherein the first gate pattern and the second gate pattern are formed in the first gate groove and the second gate groove, respectively.
9. The method of claim 1 , further comprising:
patterning the semiconductor substrate to form a first fin and a second fin on the first region and the second region, respectively, before the forming first and second gate dielectric layers,
wherein the first and second gate dielectric layers surround the first and second fins, respectively.
10. The method of claim 1 , wherein the forming first and second gate dielectric layers comprises anisotropically etching the gate electrode layer, the second metal-containing layer, the first metal-containing layer, the first gate dielectric layer, and the second gate dielectric layer using a mask pattern defining the first and second gate patterns.
11. The method of claim 1 , further comprising:
forming first source/drain regions in the semiconductor substrate on opposite sides of the first gate pattern; and
forming second source/drain regions in the semiconductor substrate on opposite sides of the second gate pattern, wherein
the first gate pattern and the first source/drain regions constitute a first transistor,
the second gate pattern and the second source/drain regions constitute a second transistor, and
temperatures of the first and second annealing processes are controlled to adjust threshold voltages of the first and second transistors.
12. The method of claim 1 , further comprising:
forming first source/drain regions in the semiconductor substrate on opposite sides of the first gate pattern; and
forming second source/drain regions in the semiconductor substrate on opposite sides of the second gate pattern, wherein
the first gate pattern and the first source/drain regions constitute a first transistor,
the second gate pattern and the second source/drain regions constitute a second transistor, and
types of gases supplied in the first and second annealing processes are controlled to adjust threshold voltages of the first and second transistors.
13. The method of claim 1 , further comprising:
forming first source/drain regions in the semiconductor substrate on opposite sides of the first gate pattern; and
forming second source/drain regions in the semiconductor substrate on opposite sides of the second gate pattern, wherein
the first gate pattern and the first source/drain regions constitute a first transistor,
the second gate pattern and the second source/drain regions constitute a second transistor, and
thicknesses of the first and second metal-containing layers are controlled to adjust threshold voltages of the first and second transistors.
14. A method of fabricating a semiconductor device, the method comprising:
forming a first gate dielectric layer and a second gate dielectric layer on a first region and a second region that are included in a semiconductor substrate, respectively;
forming a first metal-containing layer on the first and second gate dielectric layers;
forming a mask pattern to cover the first metal-containing layer on the first region;
performing a first annealing process with respect to the first metal-containing layer exposed through the mask pattern;
removing the mask pattern;
forming a second metal-containing layer on the first metal-containing layer;
performing a second annealing process with respect to the second metal-containing layer;
forming a gate electrode layer on the second metal-containing layer;
partially removing the gate electrode layer, the second metal-containing layer, the first metal-containing layer, the first gate dielectric layer, and the second gate dielectric layer to form a first gate pattern and a second gate pattern on the first region and the second region, respectively; and
performing a third annealing process after the removing the mask pattern and before the forming the second metal-containing layer.
15. A method of fabricating a semiconductor device, the method comprising:
forming an interlayer dielectric layer on a substrate having a first region and a second region;
forming a first groove and a second groove in the interlayer dielectric layer at the first region and the second region, respectively;
forming a first metal-containing layer in the first groove and the second groove;
performing a first annealing process with respect to the first metal-containing layer;
removing the first metal-containing layer in the first groove;
forming a second metal-containing layer in the first groove and the second groove;
performing a second annealing process with respect to the second metal-containing layer;
partially removing the second metal-containing layer to expose a top surface of the interlayer dielectric layer; and
performing a third annealing process after the removing the first metal-containing layer in the first groove and before the forming the second metal-containing layer.
16. The method of claim 15 , wherein the partially removing of the second metal-containing layer includes performing a planarization process with respect to the second metal-containing layer and the first metal-containing layer.
17. The method of claim 15 , wherein the first metal-containing layer and the second metal-containing layer include titanium nitride (TiN), a tantalum nitride (TaN), a titanium aluminum carbide (TiAlC), aluminum (Al), or lanthanum (La), respectively.
18. The method of claim 15 , wherein the first annealing process and the second annealing process includes supplying a reducing gas or an oxidizing gas, respectively.
19. The method of claim 18 , wherein the reducing gas includes at least one of hydrogen (H 2 ), nitrogen (N 2 ), and ammonia (NH 3 ) and the oxidizing gas includes at least one of oxygen (O 2 ), ozone (O 3 ), nitrogen monoxide (NO), and nitrogen dioxide (NO 2 ).