Electronic device including a memory array and conductive lines
View Patent ↗An electronic circuit can include a first memory cell and a second memory cell. In one embodiment, source/drain regions of the first and second memory cells can be electrically connected to each other. The source/drain regions may electrically float regardless of direction in which carriers flow through channel regions of the memory cells. In another embodiment, the first memory cell can be electrically connected to a first gate line, and the second memory cell can be electrically connected to a greater number of gate lines as compared to the first memory cell. In another aspect, the first and second memory cells are connected to the same bit line. Such bit line can electrically float when programming or reading the first memory cell or the second memory cell or any combination thereof.
1. An electronic device comprising:
a first bit line;
a second bit line;
a third bit line;
a first set of memory cells including a first memory cell, wherein;
each memory cell within the first set of memory cells has a first source/drain region and a second source/drain region;
the first source/drain region of each memory cell within the first set of memory cells is electrically connected to the first bit line; and
the second source/drain region of each memory cell within the first set of memory cells is electrically connected to the third bit line;
a second set of memory cells including a second memory cell, wherein:
each memory cell within the second set of memory cells has a first source/drain region and a second source/drain region;
the first source/drain region of each memory cell within the second set of memory cells is electrically connected to the second bit line; and
the second source/drain region of each memory cell within the first and second sets of memory cells is electrically connected to one another and to the third bit line;
a control module coupled to the first and second bit lines, wherein the electronic device is configured such that carriers can flow (1) from the first bit line to the second bit line via the second source/drain regions of the first and second memory cells or (2) from the second bit line to the first bit line via the second source/drain regions of the first and second memory cells.
2. The electronic device of claim 1 , wherein each of the first and second memory cells comprises a nonvolatile memory cell.
3. The electronic device of claim 2 , wherein each of the first and second memory cells comprises discontinuous storage elements.
4. The electronic device of claim 1 , wherein the third bit line is only electrically connected to the first memory cell, the second memory cell, the first set of memory cells, and the second set of memory cells.
5. The electronic device of claim 1 , wherein:
the first memory cell is configured to store up to a first number of bits; and
the second memory cell is configured to store up to a second number of bits that is different from the first number of bits.
6. The electronic device of claim 1 , further comprising a third bit line that is electrically connected to the first and second memory cells and electrically floats.
7. The electronic device of claim 6 , wherein the third bit line is configured to electrically float when programming, erasing, and reading the first memory cell.
8. The electronic device of claim 7 , wherein the third bit line is configured to electrically float when programming, erasing, and reading the second memory cell.
9. The electronic device of claim 1 , wherein the third bit line electrically floats.
10. The electronic device of claim 1 , wherein the third bit line is configured to electrically float when programming, erasing, and reading the first memory cell.
11. The electronic device of claim 10 , wherein the third bit line is configured to electrically float when programming, erasing, and reading the second memory cell.
12. The electronic device of claim 5 , wherein the first memory cell is configured to store twice as many bits as compared to the second memory cell.
13. The electronic device of claim 12 , further comprising:
a first gate line electrically connected to a first gate electrode of the first memory cell;
a second gate line electrically connected to a second gate electrode of the first memory cell; and
a third gate line electrically connected to a gate electrode of the second memory cell, wherein the first, second, and third gate lines are different gate lines, and the third gate line is an only gate line electrically connected to the second memory cell.
14. The electronic device of claim 13 , wherein:
a first set of discontinuous storage elements lies between the first gate electrode and a substrate, wherein the first set of discontinuous storage elements is configured to store a first set of bits within the first memory cell; and
a second set of discontinuous storage elements lies between the second gate electrode and the substrate, wherein the second set of discontinuous storage elements is configured to store a second set of bits within the first memory cell.
15. The electronic device of claim 14 , wherein:
the first set of discontinuous storage elements overlies a primary surface of the substrate;
the second set of discontinuous storage elements lies at elevations between the primary surface of the substrate and a ledge within a trench within the substrate; and
a third set of discontinuous storage elements lies between the gate electrode of the second memory cell and the substrate, and at elevations between the ledge and a bottom of the trench.
16. The electronic device of claim 1 , further comprising:
a first gate line electrically connected to a first gate electrode of the first memory cell; and
a second gate line electrically connected to a second gate electrode of the second memory cell, wherein the first and second gate lines are different gate lines.
17. The electronic device of claim 16 , wherein:
a first set of discontinuous storage elements lies between the first gate electrode and a substrate, wherein the first set of discontinuous storage elements is configured to store a first set of bits within the first memory cell; and
a second set of discontinuous storage elements lies between the second gate electrode and the substrate, wherein the second set of discontinuous storage elements is configured to store a second set of bits within the second memory cell.
18. The electronic device of claim 17 , wherein the first memory cell and the second memory cell are configured to store a same number of bits.
19. The electronic device of claim 17 , wherein:
the first set of discontinuous storage elements lies at elevations between the primary surface of the substrate and a ledge within a trench within the substrate; and
the second set of discontinuous storage elements lies at elevations between the ledge and a bottom of the trench.