ONO fabrication process for increasing oxygen content at bottom oxide-substrate interface in flash memory devices
View Patent ↗Process for reducing charge leakage in a SONOS flash memory device, including in one embodiment, forming a bottom oxide layer of an ONO structure on the semiconductor substrate to form an oxide/silicon interface having a first oxygen content adjacent the oxide/silicon interface; treating the bottom oxide layer to increase the first oxygen content to a second oxygen content adjacent the oxide/silicon interface; and depositing a nitride charge-storage layer on the bottom oxide layer. In another embodiment, process for reducing charge leakage in a SONOS flash memory device, including forming a bottom oxide layer of an ONO structure on a surface of the semiconductor substrate having an oxide/silicon interface with a super-stoichiometric oxygen content adjacent the oxide/silicon interface; and depositing a nitride charge-storage layer on the bottom oxide layer.
1. A process for reducing charge leakage in a SONOS flash memory device, comprising:
providing a semiconductor substrate;
forming a bottom oxide layer of an ONO structure on a surface of the semiconductor substrate having an oxide/silicon interface with a super-stoichiometric oxygen content adjacent the oxide/silicon interface, wherein the super-stoichiometric oxygen content is in the bottom oxide layer as initially formed; and
depositing a charge-storage layer on the bottom oxide layer.
2. The process of claim 1 , wherein the bottom oxide layer having the super-stoichiometric oxygen content adjacent the oxide/silicon interface exhibits a reduced charge leakage relative to a bottom oxide layer having a sub-stoichiometric oxygen content adjacent the oxide/silicon interface.
3. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out by decoupled plasma oxidation in an oxidizing atmosphere.
4. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out by remote plasma oxidation in an oxidizing atmosphere.
5. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out comprising ozone as an oxidizing agent.
6. The process of claim 5 , further comprising an ozone pre-clean of the surface of the substrate.
7. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out by an extended CVD or thermal oxidation at a temperature ranging from about 200° C. to about 600° C. in an oxidizing atmosphere, until the oxygen content of the bottom oxide layer becomes super-stoichiometric.
8. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out by a combination of alternating thermal oxidation and HTO deposition.
9. The process of claim 1 , wherein the step of forming the bottom oxide layer is carried out by radical oxidation.
10. The process of claim 1 , wherein the charge storage layer comprises a nitride charge storage material.
11. The process of claim 1 , wherein the bottom oxide layer comprises a high-K dielectric material.
12. The process of claim 1 , wherein the charge storage layer comprises a high-K dielectric material.
13. A process for reducing charge leakage in a SONOS flash memory device, comprising:
providing a semiconductor substrate;
forming a bottom oxide layer of an ONO structure on a surface of the semiconductor substrate having an oxide/silicon interface with a super-stoichiometric oxygen content adjacent the oxide/silicon interface, wherein the super-stoichiometric oxygen content is in the bottom oxide layer as Initially formed and the bottom oxide layer having the super-stoichiometric oxygen content adjacent the oxide/silicon interface exhibits a reduced charge leakage relative to a bottom oxide layer having a sub-stoichiometric oxygen content adjacent the oxide/silicon interface; and
depositing a nitride charge-storage layer on the bottom oxide layer.
14. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out by decoupled plasma oxidation in an oxidizing atmosphere.
15. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out by remote plasma oxidation in an oxidizing atmosphere.
16. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out comprising ozone as an oxidizing agent.
17. The process of claim 16 , further comprising an ozone pre-clean of the surface of the substrate.
18. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out by an extended CVD or thermal oxidation at a temperature ranging from about 200° C. to about 600° C. in an oxidizing atmosphere, until the oxygen content of the bottom oxide layer becomes super-stoichiometric.
19. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out by a combination of alternating thermal oxidation and HTO deposition.
20. The process of claim 13 , wherein the step of forming the bottom oxide layer is carried out by radical oxidation.
21. The process of claim 13 , wherein the bottom oxide layer comprises a high-K dielectric material.