Abstract: A pair of reference cells 77 and 78 has the same structure as that of memory cells 51 and 52 and is arranged in the same direction on a semiconductor substrate. The memory cell 51 and the reference cell 77 (even cell) are coincident in their source/drain direction. The memory cell 52 and the reference cell 78 (odd cell) are coincident in their source/drain direction. A selection circuit 79 selects the reference cell 77 when the memory cell 51 is selected, whereas the selection circuit 79 selects the reference cell 78 when the memory cell 52 is selected. In this configuration, a semiconductor memory device is provided which can prevent erroneous read and provide stable read-out characteristic irrespectively of a change in a manufacturing process.

Abstract: A first bit line BLa0 and a second bit line BLb0 are arranged for a single bit line BL0. A memory cell array is divided into a plurality of memory cell array blocks. On both opposite sides of the memory cell array 11, select transistors Q0, Q1 and Q4, Q5 and discharge transistors Q2, Q3 and Q6, Q7 are arranged. On the further outsides arranged are an electrode wiring 20 for applying a predetermined potential ARGBD and electrode wirings 21 and 22 for applying the control signals DCBLa and DCBLb. A plurality of units, each including the memory cell array block, the control transistors and control signals, are arranged. Main bit lines each passing through these units are extended so that they are connected to the select transistors of each unit pattern. In such a configuration, the capacitive load of bit lines owing to high integration of a non-volatile semiconductor memory is reduced, thereby realizing the high speed operation of the memory.

Abstract: A memory cell array 11 is divided into plural blocks in such a manner that a first and a second split bit line BLa and BLb0 are provided for a single main bit BL0. On both opposite sides of the memory cell array 11, select transistors Q0, Q1 and Q4, Q5 and discharge transistors Q2, Q3 and Q6, Q7 are arranged. Further, on both sides of the memory cell array, a wiring 20 at a predetermined potential ARGND and wirings 21 and 22 for select control signals DCBLa and DCBLb are arranged. A second gate electrode wiring 23 connects the gate of the first select transistor Q0, that of the second discharge transistor (corresponding to Q3) relative to the adjacent main bit line and the wiring 21. A first gate electrode wiring 25 connects the gate of the second select transistor Q1, that of the first discharge transistor Q2 and the wiring 21.