| 摘要 |
PURPOSE: To make a mis-alignment margin to be small so as to reduce cell area by forming a contact for connection to an active area before an accumulation polysilicon layer is formed. CONSTITUTION: Foreign substance layers 8 and 10 for ohmic contact are respectively formed between first and second accumulation polysilicon layers 7 and 9 and second and third accumulation polysilicon layers 9 and 11, and they are surrounded with a polysilicon film 12, a dielectric film 13 and a plate electrode 14. An active area 5 formed on a semiconductor substrate 1 is directly brought into contact with the polysilicon layer 7 through a contact 6. The foreign substance layers 8 and 10 are made of silicide, e.g. WSix, metal, e.g. W and Ti, and metallic compound, e.g. TiN and Cu compound. A mis-alignment margin is made small and the polysilicon layer is subject to self-alignment, so that an accumulation polysilicon layer having lamination structure can be formed easily and the cell area be also reduced so as to prevent the reduction of accumulation capacity. |
