Adjacent wordline disturb reduction using boron/indium implant
View Patent ↗Semiconductor devices having reduced parasitic current and methods of malting the semiconductor devices are provided. Further provided are memory devices having reduced adjacent wordline disturb. The memory devices contain wordlines formed over a semiconductor substrate, wherein at least one wordline space is formed between the wordlines. Adjacent wordline disturb is reduced by implanting one or more of indium, boron, and a combination of boron and indium in the surface of the at least one wordline space.
1. A semiconductor device comprising:
a semiconductor substrate;
two or more parallel bitlines formed within the semiconductor substrate;
a charge storage layer capable of storing a negative charge formed over the semiconductor substrate and the two or more parallel bitlines;
two or more parallel wordlines formed over the charge storage layer, the semiconductor substrate and the two or more parallel bitlines, the two or more parallel wordlines being perpendicular to the two or more parallel bitlines;
one or more wordline spaces comprising the area between the two or more parallel wordlines; and
an implant comprising at least one of boron, indium, and a combination thereof embedded into the floor of at least one space of the one or more wordline spaces, wherein the implant forms an implant region which is adjacent the two or more parallel wordlines and located over the charge storage layer and the semiconductor substrate.
2. The semiconductor device of claim 1 , wherein the semiconductor device comprises an array of memory cells formed at areas where the two or more parallel bitlines and the two or more parallel wordlines intersect, wherein the one or more wordline spaces comprise the area between the memory cells.
3. The semiconductor device of claim 2 , wherein the threshold voltages of wordlines adjacent to a programmed memory cell or cells are about the same as the threshold voltage of wordlines not adjacent to programmed memory cells.
4. The semiconductor device of claim 1 , wherein the implant has a projected range from about 10 to about 200 nm.
5. The semiconductor device of claim 1 , wherein the implant has a projected range from about 20 to about 2000 nm.
6. The semiconductor device of claim 1 , wherein the semiconductor device is one or more of electrically programmable ROM, electrically erasable PROM, and FLASH memory.
7. The semiconductor device of claim 2 , wherein the array of memory cells comprise one or more selected from dual poly flash memory cells and dielectric charge storage memory cells.
8. The semiconductor device of claim 1 , where in the charge storage layer comprises one or more of an oxide/nitride/oxide tri-layer, an oxide/nitride bi-layer, a nitride/oxide bi-layer, an oxide/tantalum oxide bi-layer (SiO 2 /Ta 2 O 5 ), an oxide/tantalum oxide/oxide tri-layer (SiO 2 /Ta 2 O 5 /SiO 2 ), an oxide/strontium titanate bi-layer (SiO 2 /SrTiO 3 ), an oxide/barium strontium titanate bi-layer (SiO 2 /BaSrTiO 2 ), an oxide/strontium titanate/oxide tri-layer (SiO 2 /SrTiO 3 /SiO 2 ), and an oxide/strontium titanate/barium strontium titanate tri-layer (SiO 2 /SrTiO 3 /BaSrTiO 2 ).
9. The semiconductor device of claim 1 , wherein the concentration of the implant is from about 10 16 to about 10 19 atoms/cm 3 of one or more of boron, indium, and a combination of boron and indium.
10. The semiconductor device of claim 1 , further comprising:
a liner formed adjacent sidewalls of the wordline in the one or more wordline spaces, wherein the implant is embedded into the charge storage layer between the liner.
11. The semiconductor device of claim 1 , wherein a width of the one or more wordline spaces is less than about 10 μm, and wherein the one or more wordline spaces comprise the area between the two or more parallel wordlines above the two or more parallel bitlines.
12. The semiconductor device of claim 1 , wherein the implant comprises a combination of boron and indium.
13. The semiconductor device of claim 1 , wherein the implant region is contained within the one or more wordline spaces.
14. A semiconductor device comprising:
two or more parallel bitlines formed within a semiconductor substrate;
a charge storage layer capable of storing a negative charge formed over the semiconductor substrate and the two or more parallel bitlines;
two or more parallel wordlines formed over the charge storage layer, the semiconductor substrate and the two or more parallel bitlines, the two or more parallel wordlines being perpendicular to the two or more parallel bitlines;
one or more wordline spaces comprising the area between the two or more parallel wordlines; and
an implant comprising indium embedded in the floor of at least one space of the one or more wordline spaces, wherein the implant forms an implant region which is adjacent the two or more parallel wordlines and located over the charge storage layer and the semiconductor substrate.
15. The semiconductor device of claim 14 , wherein the semiconductor device comprises an array of memory cells formed at areas where the two or more parallel bitlines and the two or more parallel wordlines intersect, wherein the one or more wordline spaces comprise the area between the memory cells.
16. The semiconductor device of claim 15 , wherein the threshold voltages of wordlines adjacent to a programmed memory cell or cells are about the same as the threshold voltage of wordlines not adjacent to programmed memory cells.
17. The semiconductor device of claim 14 , where in the charge storage layer comprises one or more of an oxide/nitride/oxide tri-layer, an oxide/nitride bi-layer, a nitride/oxide bi-layer, an oxide/tantalum oxide bi-layer (SiO 2 /Ta 2 O 5 ), an oxide/tantalum oxide/oxide tri-layer (SiO 2 /Ta 2 O 5 /SiO 2 ), an oxide/strontium titanate bi-layer (SiO 2 /SrTiO 3 ), an oxide/barium strontium titanate bi-layer (SiO 2 /BaSrTiO 2 ), an oxide/strontium titanate/oxide tri-layer (SiO 2 /SrTiO 3 /SiO 2 ), and an oxide/strontium titanate/barium strontium titanate tri-layer (SiO 2 /SrTiO 3 /BaSrTiO 2 ).
18. The semiconductor device of claim 14 , wherein the concentration of the implant is from about 10 16 to about 10 19 atoms/cm 3 of one or more of boron, indium, and a combination of boron and indium.
19. The semiconductor device of claim 14 , further comprising:
a liner formed adjacent sidewalls of the wordline in the one or more wordline spaces, wherein the implant is embedded into the charge storage layer between the liner.
20. The semiconductor device of claim 14 , wherein a width of the one or more spaces is less than about 10 μm, and wherein the one or more wordline spaces comprise the area between the two or more parallel wordlines above the two or more parallel bitlines.