| 摘要 |
PURPOSE:To elevate the degree of integration and to increase a read-out speed, by constituting so as to use a contact hole in common by (k) number of memory trains. CONSTITUTION:An ROM is constituted of M number of blocks 9 provided in parallel in the lateral direction with plural memory cell trains to which M number of X-decoders 21, each 1 piece of Y-decoder 22 and Z-decoder 23, and a transistor (TR) 10 are connected in series. Also, (k) number (k=2 in the figure) of trains 8 being adjacent to each other in the same block are made 1 group, and as for the memory cell trains of the same group, the drains of each TR14 are connected in the lump by a contact hole 1. As a result, the number of contact holes is reduced to 1/k. Also, the number of gate lines 13' of a switch TR13 is also reduced to 1/k, and all of them are capable of contributing to elevation of the degree of integration. On the other hand, size of the hole 1 becomes large, but therefore, contact resistance is reduced. Also, since an area of a TR15 is widened and its conducting resistance is reduced to 1/k or less, access is executed at a high speed. |
