Low VT antifuse device

摘要

A one time programmable memory cell having an anti-fuse device with a low threshold voltage independent of core circuit process manufacturing technology is presented. A two transistor memory cell having a pass transistor and an anti-fuse device, or a single transistor memory cell having a dual thickness gate oxide, are formed in a high voltage well that is formed for high voltage transistors. The threshold voltage of the anti-fuse device differs from the threshold voltages of any transistor in the core circuits of the memory device, but has a gate oxide thickness that is the same as a transistor in the core circuits. The pass transistor has a threshold voltage that differs from the threshold voltages of any transistor in the core circuits, and has a gate oxide thickness that differs from any transistor in the core circuits. The threshold voltage of the anti-fuse device is lowered by omitting some or all of the threshold adjustment implants that is used for high voltage transistors fabricated in the I/O circuits.

主权项

1. A memory device comprising:
a memory array including a plurality of anti-fuse memory cells, each of the plurality of anti-fuse memory cells including
an access transistor having a thick gate oxide formed in a high voltage well having a high voltage well profile, the high voltage well being one of n-type and p-type, andan anti-fuse device having a thin gate oxide formed in the high voltage well, the thin gate oxide having a thickness less than the thick gate oxide; and, a core transistor having a gate oxide corresponding in thickness to the thin gate oxide, the core transistor being formed in a low voltage well having a same type as the high voltage well, the low voltage well having a low voltage well profile different from the high voltage well profile, and the low voltage well having a concentration greater than the high voltage well.