Method for fabricating a high-K dielectric layer
View Patent ↗One inventive aspect relates to a method for fabricating a high-k dielectric layer. The method comprises depositing onto a substrate a layer of a high-k dielectric material having a first thickness. The high-k dielectric material has a bulk density value and the first thickness is so that the high-k dielectric layer has a density of at least the bulk density value of the high-k dielectric material minus about 10%. The method further comprises thinning the high-k dielectric layer to a second thickness. Another inventive aspect relates to a semiconductor device comprising a high-k dielectric layer as fabricated by the method.
1. A method of fabricating a high-k dielectric layer comprising:
depositing onto a substrate a high-k dielectric material so as to form a high-k dielectric layer with a first thickness, the first thickness is selected so that the high-k dielectric layer has a density of at least the bulk density value of the high-k dielectric material minus about 10%; and
thinning the high-k dielectric layer to a second thickness, the second thickness being selected so that the high-k dielectric layer having been thinned to the second thickness has a higher density than is obtained by depositing the high-k dielectric material with the second thickness.
2. The method according to claim 1 , wherein the second thickness is at least ⅕ of the thickness at which a high-k dielectric layer deposited has a density equal to the bulk density value of the high-k dielectric material minus 10%.
3. The method according to claim 2 , wherein the second thickness is less than about ½ of the thickness at which a high-k dielectric layer deposited has a density equal to the bulk density value of the high-k dielectric material minus 10%.
4. The method according to claim 2 , wherein the second thickness is less than about ⅓ of the thickness at which a high-k dielectric layer deposited has a density equal to the bulk density value of the high-k dielectric material minus 10%.
5. The method according to claim 2 , wherein the second thickness is less than about ¼ of the thickness at which a high-k dielectric layer deposited has a density equal to the bulk density value of the high-k dielectric material minus 10%.
6. The method according to claim 1 , wherein the thinning of the high-k dielectric layer to a second thickness is performed by etching back the high-k dielectric layer.
7. The method according to claim 6 , wherein the etching back of the high-k dielectric layer is performed by a wet etching process.
8. The method according to claim 1 , wherein the second thickness is selected such that the high-K dielectric layer of the second thickness has a desired layer quality.
9. The method according to claim 8 , wherein the layer quality is defined by at least one of the following parameters: density, film closure, roughness, and electrical leakage.
10. The method according to claim 1 , wherein the high-k dielectric layer is at least one of the following: a metal oxide, metal silicate, metal oxynitride, and metal silicon oxynitride.
11. The method according to claim 1 , wherein the process of depositing the high-k dielectric layer with a first thickness and thinning the high-k dielectric layer to a second thickness are repeated sequentially.
12. The method according to claim 1 , wherein the high-k dielectric layer has a k value higher than 3.9.
13. The method according to claim 1 , wherein the high-k dielectric layer functions as gate dielectric in a field effect transistor.
14. The method according to claim 1 , wherein the first and second thickness are selected such that the high-k dielectric layer formed after the thinning process has a higher density than a density of a high-k dielectric layer formed by depositing the high-k dielectric material with the second thickness.
15. A method of fabricating a high-k dielectric layer comprising:
depositing, by a metal organic chemical vapor deposition (MOCVD)_process, a high-k dielectric layer of a first thickness, the first thickness is selected so that the high-k dielectric layer deposited has a density of at least the bulk density value of the high-k dielectric material minus about 10%; and
thinning the high-k dielectric layer to a second thickness,
wherein the second thickness is selected so that the high-k dielectric layer having been thinned to the second thickness has a higher density than is obtained by depositing the high-k dielectric material with the second thickness.