| 摘要 |
PURPOSE:To implement a high speed by decreasing the resistance value of word lines and to shorten a turnaround time, by forming the gate electrode of a cell transistor with double layers, removing a part of the upper layer, and implanting ions. CONSTITUTION:On a semiconductor substrate 1, a field oxide film 2 as an isolating and insulating layer and a gate oxide film 3 of a cell transistor are formed. A gate electrode comprising double layers, i.e., word lines WLs, is formed. The word lines WLs are constituted by a polysilicon layer 4-1 and a silicide layer 4-2. When writing is performed in the cell transistor, the layer 4-2 on the gate of the cell transistor is selectively etched away. B<+> ions and the like are implanted in a part, where the layer 4-2 is removed, and the threshold voltage value of the cell transistor is changed. Thus the writing of the data is performed. |
