Memory devices having source lines directly coupled to body regions and methods
Memory devices, memory cell strings and methods of operating memory devices are shown. Configurations described include directly coupling an elongated body region to a source line. Configurations and methods shown should provide a reliable bias to a body region for memory operations such as erasing.
1. A memory device, comprising:
a continuous elongated body region of the same conductivity type, having a source region coupled to a first end, and a drain region coupled to a second end;
a plurality of gates along a length of the elongated body region, each of the plurality of gates being separated from the elongated body region by at least a charge storage structure; and
a source line and a bitline, wherein the bitline is coupled to the drain region, and wherein the first end of the body region is directly coupled to both the source region and the source line.
2. The memory device of claim 1 , wherein the elongated body region is oriented vertically.
3. The memory device of claim 1 , wherein the elongated body region is oriented horizontally.
4. The memory device of claim 1 , wherein the elongated body region forms a “U” shape.
5. The memory device of claim 1 , further including a first select gate adjacent to a first end of the elongated body region and a second select gate adjacent to a second end of the elongated body region.
6. The memory device of claim 1 , wherein the bitline is coupled to the drain region through a conductive plug.
7. A memory device, comprising:
a continuous p type elongated body region, having an n type source region coupled to a first end, and an n type drain region coupled to a second end;
a plurality of gates along a length of the p type elongated body region, each of the plurality of gates being separated from the continuous p type body region by at least a respective charge storage structure;
a metal source line coupled to the continuous p type elongated body region at an end of the body region;
wherein the n type source region contacts an end of the continuous p type elongated body region and is also coupled to the metal source line.
8. The memory device of claim 7 , wherein at least the end of the p type elongated body region is formed from p+ doped polysilicon.
9. The memory device of claim 7 , wherein the n type source region is formed from n+ polysilicon.
10. The memory device of claim 7 , wherein the n type drain region is formed from n+ polysilicon.
11. The memory device of claim 7 , wherein the continuous p type elongated body region forms a “U” shape.
12. The memory device of claim 11 , wherein the source line is stacked on top of the n type source region.
13. A memory device, comprising:
a U shaped memory cell string, including:
an elongated body region, having a first and second upward facing end;
a drain region coupled to the first upward facing end;
a source region coupled to the second upward facing end;
a plurality of gates along a length of the elongated body region;
a data line coupled to the drain region; and
a source line coupled to the second upward facing end of the elongated body region and wherein the second upward facing end of the elongated body region is directly coupled to both the source region and the source line.
14. The memory device of claim 13 , wherein the source line and the source region are shared with an adjacent memory cell string.
15. The memory device of claim 13 , wherein the source region substantially surrounds a cross section of the second upward facing end of the elongated body region.
16. The memory device of claim 13 , wherein the gates are shared with an adjacent memory cell string.
17. The memory device of claim 16 , wherein a first portion of the gates are shared with a first adjacent memory cell string and wherein a second portion of the gates are shared with a second adjacent memory cell string.