Memory with extended charge trapping layer
View Patent ↗A memory array includes a plurality of bit lines and a plurality of word lines, a gate region, and a charge trapping layer. The charge trapping layer is wider than a word line; the charge trapping layer is extended beyond the edge of the gate region to facilitate capturing and removing charges.
1. A memory array comprising:
a plurality of bit lines; and
a plurality of word lines including a first word line and a second word line, wherein said first word line comprises a first gate region adjacent to a first charge trapping layer and adjacent to a first spacer, wherein said second word line comprises a second gate region adjacent to a second charge trapping layer and adjacent to a second spacer, each of said first and second charge trapping layers comprising a nitride layer and each of said first and second charge trapping layers between a first oxide layer and a second oxide layer, wherein said first charge trapping layer is wider than said first word line and said second charge trapping layer is wider than said second word line, wherein further the region between said first and second spacers and said first and second charge trapping layers is filled with dielectric material, said memory array further comprising an oxide region formed on each end of the nitride layers of said first and second charge trapping layers, wherein said oxide region does not extend beyond the edges of said nitride layers to said first oxide layer and to said second oxide layer, wherein said dielectric material that fills said region between said first and second spacers is in contact with said first and second oxide layers but not said nitride layers.
2. The memory array of claim 1 wherein each of said first and second gate regions comprises polysilicon.
3. The memory array of claim 1 further comprising a substrate having formed therein a source/drain region, wherein said source/drain region is located between said first and second charge trapping layers.
4. A memory device comprising:
a plurality of bit lines; and
a plurality of word lines comprising a first word line and a second word line, wherein said first word line comprises a first polysilicon region adjacent to a first charge trapping region adjacent to a first spacer, and wherein said second word line comprises a second polysilicon region adjacent to a second charge trapping region and adjacent to a second spacer, said first charge trapping region and said second charge trapping region each comprising a nitride layer and each further comprising a first oxide layer and a second oxide layer, wherein said first and second polysilicon regions are separated by a greater distance than that separating said first and second charge trapping regions, wherein further the region between said first and second spacers and said first and second charge trapping regions is filled with dielectric material, the memory device further comprising an oxide region formed on each end of the nitride layers of said first and second charge trapping regions, wherein said oxide region does not extend beyond the edges of said nitride layers to said first oxide layer and beyond the edges of said nitride layers to said second oxide layer, wherein said dielectric material that fills said region between said first and second spacers is in contact with said first and second oxide layers but is not in contact with said nitride layers.
5. The memory device of claim 4 further comprising a substrate having formed therein a source/drain region, wherein said source/drain region is located between said first and second charge trapping regions.
6. A memory device comprising:
a substrate;
a first gate region and an adjacent first spacer;
a second gate region and an adjacent second spacer;
a first charge trapping region between said substrate and said first gate region, wherein said first charge trapping region extends beyond an edge of said first gate region;
a second charge trapping region between said substrate and said second gate region, wherein said second charge trapping region extends beyond an edge of said second gate region, wherein further the region between said first and second spacers and said first and second charge trapping regions is filled with dielectric material, each of said first and second charge trapping regions comprising a nitride layer, each of said first and second charge trapping regions further comprising a first oxide layer and a second oxide layer, wherein said nitride layer is between said first and second oxide layers; and
oxide regions formed on each end of the nitride layers of said first and second charge trapping regions, wherein said oxide regions do not overlap said first oxide layer and do not overlap said second oxide layer, wherein said dielectric material that fills said region between said first and second spacers is in contact with said first and second oxide layers but is not in contact with said nitride layers.
7. The memory device of claim 6 wherein each of said first and second gate regions comprises polysilicon.
8. The memory device of claim 6 wherein said substrate comprises a source/drain region, wherein said source/drain region is adjacent said first and second charge trapping regions.
9. The memory device of claim 6 further comprising an additional oxide region between said first gate region and said first spacer.
10. The memory array of claim 1 wherein the edge of said first spacer away from said first gate region and the outer edge of said first charge trapping layer are aligned.
11. The memory device of claim 4 wherein the outer edge of said first charge trapping layer and the outer edge of said first spacer are aligned.
12. The memory device of claim 6 wherein the outer edge of said first charge trapping layer does not extend beyond the edge of said first spacer that is not adjacent to said first gate region.