CHARGE INJECTION

摘要

A system and methodology is provided for programming first bit (CO, C2, C4, C6) and second bit (C1, C3, C5, C7) of a memory array (68) of dual bit memory cells (10, 82, 84, 86, 88) at a substantially high delta VT. The substantially higher VT assures that the memory array (68) will maintain programmed data and erase data consistently after higher temperature stresses and/or custumer operation over substantial periods of time. At a substantially higher delta VT, programming of the first bit (C0, C2, C4, C6) of the memory cell (10, 82, 84, 86, 88) causes the second bit (C1, C3, C5, C7) to program harder and faster due to the shorter channel (8) length. Therefore, the present invention employs selected gate and drain voltages and programming pulse widths during programming of the first bit (C0, C2, C4, C6) and second bit (C1, C3, C5, C7) that assures a controlled first bit VT and slows down programming of the second bit (C1,C3, C5, C7). Furthermore, the selected programming parameters keep the programming times short without degrading charge loss.