Granted Patent B1

US 6,969,886 · App. 10/889,424 · Granted Nov 29, 2005

Abstract

Claims (27)

1. A SONOS flash memory device, comprising:

a semiconductor substrate;

an ONO structure formed on the semiconductor substrate, the ONO structure comprising a bottom oxide layer, a dielectric charge storage layer and a top oxide layer, the bottom oxide layer having a super-stoichiometric oxygen content and an oxygen vacancy content of about 10 10 /cm 2 or less, wherein the bottom oxide layer exhibits a reduced charge leakage relative to a bottom oxide layer having a stoichiometric or sub-stoichiometric oxygen content and a greater number of oxygen vacancies.

2. The SONOS flash memory device of claim 1 wherein the bottom oxide layer comprises a high-K dielectric material.

3. The SONOS flash memory device of claim 2 wherein the high-K dielectric material comprises one or more of ZrO 2 ; HfO 2 ; Al 2 O 3 ; Y 2 O 3 ; La 2 O 3 ; a silicate of one or more of ZrO 2 , HfO 2 , Al 2 O 3 , Y 2 O 3 , La 2 O 3 ; or an aluminate of one or more of ZrO 2 , HfO 2 , Y 2 O 3 , La 2 O 3 ; tantalum oxide (Ta 2 O 5 ); barium titanate (BaTiO 3 ); titanium dioxide (TiO 2 ); cerium oxide (CeO 2 ); lanthanum aluminum oxide (LaAlO 3 ); lead titanate (PbTiO 3 ); strontium titanate (SrTiO 3 ); lead zirconate (PbZrO 3 ); tungsten oxide (WO 3 ); bismuth silicon oxide (Bi 4 Si 2 O 12 ); barium strontium titanate (BST) (Ba 1-x Sr x TiO 3 ); PMN (PbMg x Nb 1-x O 3 ); PZT (PbZr x Ti 1-x O 3 ); PZN (PbZn x Nb 1-x O 3 ); PST (PbSc x Ta 1-x O 3 ); lead lanthanum titanate; strontium bismuth tantalate; bismuth titanate; and barium zirconium titanate.

4. The SONOS flash memory device of claim 2 wherein the high-K dielectric material is other than tantalum oxide, Ta 2 O 5 .

5. The SONOS flash memory device of claim 1 wherein the bottom oxide comprises a composite dielectric material.

6. The SONOS flash memory device of claim 1 wherein the bottom oxide layer comprises SiO x , wherein x>2.

7. The SONOS flash memory device of claim 1 wherein the charge storage layer is a nitride charge storage material.

8. The SONOS flash memory device of claim 7 wherein the charge storage layer comprises silicon nitride.

9. A SONOS flash memory device, comprising:

a semiconductor substrate;

an ONO structure formed on the semiconductor substrate, the ONO structure comprising a bottom oxide layer, a dielectric charge storage layer and a top oxide layer, the bottom oxide layer having a super-stoichiometric oxygen content and an oxygen vacancy content of substantially zero, wherein the bottom oxide layer exhibits a reduced charge leakage relative to a bottom oxide layer having a stoichiometric or sub-stoichiometric oxygen content and a substantial number of oxygen vacancies.

10. The SONOS flash memory device of claim 9 wherein the bottom oxide layer comprises a high-K dielectric material.

11. The SONOS flash memory device of claim 10 wherein the high-K dielectric material comprises one or more of ZrO 2 ; HfO 2 ; Al 2 O 3 ; Y 2 O 3 ; La 2 O 3 ; a silicate of one or more of ZrO 2 , HfO 2 , Al 2 O 3 , Y 2 O 3 , La 2 O 3 ; or an aluminate of one or more of ZrO 2 , HfO 2 , Y 2 O 3 , La 2 O 3 ; tantalum oxide (Ta 2 O 5 ); barium titanate (BaTiO 3 ); titanium dioxide (TiO 2 ); cerium oxide (CeO 2 ); lanthanum aluminum oxide (LaAlO 3 ); lead titanate (PbTiO 3 ); strontium titanate (SrTiO 3 ); lead zirconate (PbZrO 3 ); tungsten oxide (WO 3 ); bismuth silicon oxide (Bi 4 Si 2 O 12 ); barium strontium titanate (BST) (Ba 1-x Sr x TiO 3 ); PMN (PbMg x Nb 1-x O 3 ); PZT (PbZr x Ti 1-x O 3 ); PZN (PbZn x Nb 1-x O 3 ); PST (PbSc x Ta 1-x O 3 ); lead lanthanum titanate; strontium bismuth tantalate; bismuth titanate; and barium zirconium titanate.

12. The SONOS flash memory device of claim 10 wherein the high-K dielectric material is other than tantalum oxide, Ta 2 O 5 .

13. The SONOS flash memory device of claim 9 wherein the bottom oxide comprises a composite dielectric material.

14. The SONOS flash memory device of claim 9 wherein the bottom oxide layer comprises SiO x , wherein x>2.

15. The SONOS flash memory device of claim 9 wherein the charge storage layer is a nitride charge storage material.

16. The SONOS flash memory device of claim 15 wherein the charge storage layer comprises silicon nitride.

17. A SONOS flash memory device, comprising:

a semiconductor substrate;

an ONO structure formed on the semiconductor substrate, the ONO structure comprising a bottom oxide layer, a nitride charge storage layer and a top oxide layer, the bottom oxide layer having a super-stoichiometric oxygen content and an oxygen vacancy content of about 10 10 /cm 2 or less, wherein the bottom oxide layer exhibits a reduced charge leakage relative to a bottom oxide layer having a stoichiometric or sub-stoichiometric oxygen content and a greater number of oxygen vacancies,

wherein the bottom oxide layer comprises silicon dioxide, a high-K dielectric material or a composite dielectric material.

18. The SONOS flash memory device of claim 17 wherein the charge storage layer comprises silicon nitride.

19. The SONOS flash memory device of claim 17 wherein the silicon dioxide has a formula SiO x , wherein x>2.

20. The SONOS flash memory device of claim 17 wherein the high-K dielectric material comprises one or more of ZrO 2 ; HfO 2 ; Al 2 O 3 ; Y 2 O 3 ; La 2 O 3 ; a silicate of one or more of ZrO 2 , HfO 2 , Al 2 O 3 , Y 2 O 3 , La 2 O 3 ; or an aluminate of one or more of ZrO 2 , HfO 2 , Y 2 O 3 , La 2 O 3 ; tantalum oxide (Ta 2 O 5 ); barium titanate (BaTiO 3 ); titanium dioxide (TiO 2 ); cerium oxide (CeO 2 ); lanthanum aluminum oxide (LaAlO 3 ); lead titanate (PbTiO 3 ); strontium titanate (SrTiO 3 ); lead zirconate (PbZrO 3 ); tungsten oxide (WO 3 ); bismuth silicon oxide (Bi 4 Si 2 O 12 ); barium strontium titanate (BST) (Ba 1-x Sr x TiO 3 ); PMN (PbMg x Nb 1-x O 3 ); PZT (PbZr x Ti 1-x O 3 ); PZN (PbZn x Nb 1-x O 3 ); PST (PbSc x Ta 1-x O 3 ); lead lanthanum titanate; strontium bismuth tantalate; bismuth titanate; and barium zirconium titanate.

Assignments (8)