| 摘要 |
PURPOSE:To prevent silicon from being mixed into tantalum, by constituting a storage capacitor of a dynamic random access memory formed on a silicon substrate, with a lower electrode, silicon nitride film, tantalum pentoxide film, silicon nitride film, tantalum pentoxide film and upper electrode. CONSTITUTION:A polysilicon film forming a lower electrode 7 and a silicon nitride film 8 are sequentially formed. On the silicon nitride film, Ta is deposited which is thermal-oxidized to form a Ta2O5 film 9. On the Ta2O5 film 9, a silicon nitride film 10 is formed, on which Ta is deposited and is thermal-oxidized to form a Ta2O5 film 11. Next, a polysilicon film for forming an upper electrode 12 is formed. Thereafter, this five-layer films are patterned, for example with dry etching. Since the Ta2O5 film 9 is put between the silicon nitride films 8 and 10, silicon is prevented from being mixed from the lower electrode 7 into the Ta2O5 film 9 when making it by thermal-oxidizing Ta. Moreover, the Ta2O5 film 11 and upper electrode 12 also act in the same way. |
