Method of enhancing high-k film nucleation rate and electrical mobility in a semiconductor device by microwave plasma treatment
A method for forming a semiconductor device is provided in several embodiments. According to one embodiment, the method includes providing a substrate in a process chamber, flowing a process gas consisting of hydrogen (H 2 ) and optionally a noble gas into the process chamber, forming plasma excited species from the process gas by a microwave plasma source. The method further includes exposing an interface layer on the substrate to the plasma excited species to form a modified interface layer, and depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified interface layer. In some embodiments, the modified interface layer has higher electrical mobility than the interface layer, and the high-k film nucleates at a higher rate on the modified interface layer rate than on the interface layer.
1. A method for forming a semiconductor device, the method comprising:
providing a substrate in a process chamber;
flowing a process gas consisting of hydrogen (H 2 ) and optionally a noble gas into the process chamber;
forming plasma excited species from the process gas by a microwave plasma source;
exposing an interface layer on the substrate to the plasma excited species to form a modified interface layer; and
depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified interface layer.
2. The method of claim 1 , wherein the modified interface layer has higher electrical mobility than the interface layer.
3. The method of claim 1 , wherein the high-k film nucleates at a higher rate on the modified interface layer rate than on the interface layer.
4. The method of claim 1 , wherein the interface layer includes an oxide layer, an oxynitride layer, or a nitride layer, or a combination thereof.
5. The method of claim 1 , wherein exposing the interface layer to the plasma excited species reduces a thickness of the interface layer.
6. The method of claim 1 , further comprising
forming the interface layer on the substrate in the process chamber.
7. The method of claim 6 , wherein forming the interface layer comprises
exposing the substrate to sequential pulses of ozone and water.
8. The method of claim 6 , wherein forming the interface layer comprises
exposing the substrate to plasma exited species formed by microwave plasma excitation of O 2 and optionally a noble gas.
9. The method of claim 6 , wherein an initial oxide layer is removed from the substrate prior to forming the interface layer on the substrate.
10. The method of claim 9 , wherein the initial oxide layer is removed by a chemical oxide removal (COR) process or by exposure to wet dilute hydrofluoric acid (DHF).
11. The method of claim 1 , wherein the providing comprises
providing the substrate in a process chamber, wherein a surface of the substrate is at least substantially free of oxygen; and
forming the interface layer on the substrate in the process chamber.
12. The method of claim 1 , further comprising depositing a metal-containing gate electrode film on the high-k film.
13. The method of claim 12 , further comprising
patterning the metal-containing gate electrode film, the high-k film, and the modified interface layer to form a gate stack on the substrate.
14. The method of claim 1 , wherein the substrate contains silicon, germanium, silicon germanium, or a compound semiconductor.
15. A method for forming a semiconductor device, the method comprising:
providing a substrate in a process chamber;
flowing a process gas consisting of hydrogen (H 2 ) and optionally a noble gas into the process chamber;
forming plasma excited species from the process gas by a microwave plasma source;
exposing an interface layer on the substrate to the plasma excited species to form a modified interface layer with increased electrical mobility, wherein the exposing reduces a thickness of the interface layer; and
depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified interface layer; wherein the high-k film nucleates at a higher rate on the modified interface layer rate than on the interface layer.
16. The method of claim 15 , wherein the providing comprises
providing the substrate in a process chamber, wherein a surface of the substrate is at least substantially free of oxygen; and
forming the interface layer on the substrate in the process chamber.
17. A method for forming a semiconductor device, the method comprising:
providing a germanium-containing substrate in a process chamber;
flowing a process gas consisting of hydrogen (H 2 ) and optionally a noble gas into the process chamber;
forming plasma excited species from the process gas by a microwave plasma source;
exposing a germanium-containing interface layer on the substrate to the plasma excited species to form a modified germanium-containing interface layer with increased electrical mobility; and
depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified germanium-containing interface layer, wherein the high-k film nucleates at a higher rate on the modified germanium-containing interface layer rate than on the germanium-containing interface layer.
18. The method of claim 17 , wherein the germanium-containing substrate includes Ge or SiGe.
19. The method of claim 17 , wherein the germanium-containing interface layer includes germanium oxide.
20. The method of claim 17 , wherein exposing the germanium-containing interface layer to the plasma excited species reduces a thickness of the germanium-containing interface layer.