| 摘要 |
PROBLEM TO BE SOLVED: To increase the capacitance of a dynamic RAM by removing a part of silicon nitride and a part of first polysilicon by etching and then removing the silicon nitride entirely. SOLUTION: A silicon nitride 17 is deposited on a polysilicon 16 forming the lower electrode of a capacitor and then the silicon nitride 17 is etched using phosphoric acid. Since a part of the silicon nitride 17 containing many crystal defects is etched quickly, an opening is made selectively in the silicon nitride 17. The polysilicon 16 is then etched by KOH solution using the silicon nitride 17 as a mask thus forming irregularities on the surface. Subsequently, ONO film 18 is deposited and the upper electrode 19 of capacitor is formed. |
