Multi-bit programmable memory cell having multiple anti-fuse elements
AssigneeTower Semiconductor Ltd.
InventorsIshai Nachumovsky, Yaov Nissan-Cohen, Robert J. Strain
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Abstract
A multi-bit programmable memory cell is provided that includes an access transistor and a plurality of N anti-fuse elements. The access transistor has a source coupled to a source line and a gate coupled to a word line. Each of the anti-fuse elements has a first terminal coupled to a drain of the access transistor, and a second terminal coupled to a corresponding bit line. At most, only one of the anti-fuse elements is programmed. The memory cell is capable of storing M bits, wherein N=2M−1. A method is provided for both programming and reading the memory cell. In another embodiment, the anti-fuse elements can be replaced with mask-programmable elements.
Claims2
A mask programmable read-only memory (ROM) cell comprising:
- an access transistor having a source coupled to a source line, a gate coupled to a word line, and a drain;
- a plurality of bit lines associated with the access transistor;
- and
- a pattern of conductive and non-conductive regions located between the bit lines and the drain of the access transistor, wherein the pattern of conductive and non-conductive regions are mask programmed, and wherein each conductive region couples the drain of the access transistor to one of the bit lines, and each non-conductive region isolates the drain of the access transistor from one of the bit lines.
Dependencies are inferred from the claim text.