| 摘要 |
A one-time programmable ("OTP") memory includes one or more memory arrays (700) stacked on top of each other. The OTP memory array (700) is a cross-point array where unit memory cells (790) are formed at the cross-points. The unit memory cell (790) may include a fuse (230, 330) and an anti-fuse (280, 380) in series with each other or may include a vertically oriented fuse (430, 530). Programming the memory may include the steps of selecting unit memory cells (790), applying a writing voltage such that critical voltage drop across the selected cells (790) occur. This causes the anti-fuse (280, 380) of the cell (790) to break down to a low resistance. The low resistance of the anti-fuse (280, 380) causes a high current pulse to be delivered to the fuse (230, 330), which in turn melts the fuse (230, 330) to an open state. Reading the memory may include the steps of selecting unit memory cells (790) for reading, applying a reading voltage to the selected memory cells (790) and measuring whether current is present or not. Equipotential sensing may be used to read the memory. <IMAGE> <IMAGE> |
