| 摘要 |
PURPOSE: To obtain a mask ROM constituted in such a planar structure that can operate at a high speed. CONSTITUTION: Word lines 28 which are composed of belt-like low-resistance metallic layers extended in the direction perpendicular to the extending direction of bit lines 26 are formed on a P-type silicon substrate 20. Polysilicon gate electrodes 32 which are separated from each at every memory transistor and separated from the substrate 20 by gate oxide films 30 are formed in the areas between each adjacent bit lines 26 and 26. A silicon oxide film 34 is formed on the gate electrodes 32 except the electrode 32 which is turned on in accordance with information to be stored when the memory transistor on the electrode 32 is selected and on which a contact hole 36 is formed and the gate electrode 32 of the memory transistor is connected to the word lines 28 through the contact hole 36. |
