| 摘要 |
PURPOSE:To realize high speed operation and improve the stability of the operation by a method wherein the surface electrodes of capacitors, the gates of FET's and a digit line are composed of first, second and third polycrystalline layers, respectively, and word lines are composed of metal layers. CONSTITUTION:Second polycrystalline silicon layers 30A and 30B provided on silicon oxide films 12a and 12b are used as the gate electrodes of 1st and 2nd FET's. Then a digit line connected to an N-type common source region 18 is composed of a polycrystalline silicon layer 32 and word lines perpendicular to the digit line are composed of metal layers 36A and 36B. The parts of the metal layers 36A and 36B are brought into ohmic contact with the gate polycrystalline silicon layers 30A and 30B through corresponding contact holes formed in an interlayer insulating film 34. The sheet resistances of the layers 36A and 36B, therefore, are reduced and the resistances of the word lines are reduced. With this constitution, high speed operation can be realized and, further, the stability of the operation can be improved. |
