DRAM cell with a comb-type capacitor

摘要

An efficient method for manufacturing a comb-type capacitor for use as part of a DRAM cell in a silicon integrated circuit is described. A three toothed comb is created by first forming a central pedestal of polysilicon, providing oxide spacers on the vertical sides of said pedestal, coating said spacers with an additional layer of polysilicon, and then etching away said spacers thereby creating the comb structure. In addition to the comb, the method of the present invention also leads to the formation of a projecting rim of polysilicon that runs around all four sides of the capacitor structure, thereby further increasing its effective surface beyond that due to the comb.