| 摘要 |
PURPOSE:To prevent the formation of double stepped structure in tapered etching, rising of polycrystalline silicon during oxidation and improve over-hang structure by implanting ion to the first gate electrode through oxide film and generating damage only on the surface area, with regard to preparation of semiconductor device having double gate electrode structure. CONSTITUTION:A coated film 26 is formed on the surface of first electrode material film 25, impurity is implanted through such film and damage is generated in the area near the surface of electrode material film 25. Thereby, after the coated film 26 is removed, the electrode material film 25 is etched using mask material and thereby the lower electrode 28 having the tapered stepped portion can be formed. The insulating film and the second electrode material film 33 are formed covering the tapered stepped portion on the surface of electrode material film 25. Next, the electrode material film 33 is patterned into the desired shape, thereby forming the upper electrode 33. |
