Ferroelectric structure for semiconductor devices
The present disclosure relates to a semiconductor device includes a substrate and first and second spacers on the substrate. The semiconductor device includes a gate stack between the first and second spacers. The gate stack includes a gate dielectric layer having a first portion formed on the substrate and a second portion formed on the first and second spacers. The first portion includes a crystalline material and the second portion comprises an amorphous material. The gate stack further includes a gate electrode on the first and second portions of the gate dielectric layer.
1. A method, comprising:
forming a pair of opposing spacers on a fin;
depositing an amorphous dielectric layer in an opening between the pair of opposing spacers, comprising:
depositing a first portion of the amorphous dielectric layer on the fin; and
depositing a second portion of the amorphous dielectric layer on sidewalls of the pair of opposing spacers; and
performing a plasma treatment on the amorphous dielectric layer, wherein the plasma treatment converts the first portion of the amorphous dielectric layer into a crystalline dielectric layer without converting the second portion of the amorphous dielectric layer.
2. The method of claim 1 , wherein depositing the amorphous dielectric layer comprises depositing a hafnium-based oxide material.
3. The method of claim 1 , wherein the crystalline dielectric layer comprises a crystalline ferroelectric material.
4. The method of claim 1 , wherein performing the plasma treatment comprises applying a radio frequency (RF) plasma using argon and ammonia gas mixtures or argon and nitrogen gas mixtures.
5. The method of claim 1 , wherein performing the plasma treatment comprises applying an RF plasma on the amorphous dielectric layer anisotropically.
6. The method of claim 5 , wherein a power of the RF plasma is between about 500 W and about 2500 W.
7. The method of claim 1 , wherein the first portion of the amorphous dielectric layer extends under the second portion of the amorphous dielectric layer.
8. The method of claim 1 , further comprising depositing a conductive structure in contact with the crystalline dielectric layer and the second portion of the amorphous dielectric layer.
9. The method of claim 1 , wherein the second portion of the amorphous dielectric layer is in contact with the fin.
10. The method of claim 1 , wherein the plasma treatment is performed at a temperature between about 500° C. and about 900° C.
11. A method, comprising:
forming a fin;
forming first and second spacers on the fin;
depositing an amorphous dielectric layer on an interface layer, comprising:
depositing a first portion of the amorphous dielectric layer on a top surface of the fin; and
depositing a second portion of the amorphous dielectric layer on the top surface of the fin and on sidewalls of the first and second spacers; and
performing a plasma treatment on the amorphous dielectric layer, wherein the plasma treatment converts the first portion of the amorphous dielectric layer into a crystalline dielectric layer.
12. A method, comprising:
forming a fin;
forming first and second spacers on the fin;
depositing an amorphous dielectric layer, comprising:
depositing a first portion of the amorphous dielectric layer on the fin; and
depositing a second portion of the amorphous dielectric layer on sidewalls of the first and second spacers;
converting, by a plasma treatment on the amorphous layer, the first portion of the amorphous dielectric layer into a crystalline dielectric layer; and
forming a gate electrode on the crystalline dielectric layer and the second portion of the amorphous dielectric layer.
13. The method of claim 11 , wherein the crystalline dielectric layer comprises a crystalline ferroelectric material.
14. The method of claim 11 , wherein performing the plasma treatment comprises applying a radio frequency (RF) plasma using argon and ammonia gas mixtures or argon and nitrogen gas mixtures.
15. The method of claim 11 , further comprising forming a gate electrode on the crystalline dielectric layer and the second portion of the amorphous dielectric layer.
16. The method of claim 11 , wherein depositing the amorphous dielectric layer comprises depositing a hafnium-based oxide material.
17. The method of claim 16 , wherein depositing the amorphous dielectric layer comprises depositing a hafnium-based oxide material.
18. The method of claim 16 , wherein the crystalline dielectric layer comprises a crystalline ferroelectric material.
19. The method of claim 16 , wherein performing the plasma treatment comprises applying a radio frequency (RF) plasma using argon and ammonia gas mixtures or argon and nitrogen gas mixtures.
20. The method of claim 19 , wherein performing the plasma treatment comprises applying the RF plasma on the amorphous dielectric layer anisotropically.