Fabrication of higher value MOS DRAM capacitors with increased capacitor surface area

摘要

An isolating layer (3) with a contact hole and isolation film spacer (5) is built on the substrate (1) on which a conducting layer (7) is deposited. Above this three sacrificial layers in cylindrical or rectangular shape are deposited with the top and bottom layers (9) (13) overlapping the middle (11) to create a former for building the capacitor sidewalls. Polysilicon films (17) (23) are then deposited on the former with an oxide-film spacer (19) in a sandwich structure. The sacrificial former (9) (11) (13) and the oxide-film spacer (19) are then etched away to leave the capacitor sidewalls (25). If necessary, more polysilicon layers may be added for a higher capacitance.