Method to achieve rough silicon surface on both sides of container for enhanced capacitance/area electrodes

Abstract

A method and apparatus for enhanced capacitance per unit area electrodes is utilized in semiconductor memory devices. The capacitance is enhanced by roughening the surface of the bottom electrode in such devices. In one embodiment of the invention, surface roughness is achieved on a polysilicon bottom capacitor electrode by depositing doped polysilicon on the outside surfaces of a bottom capacitor electrode and vacuum annealing. In another embodiment of the invention, surface roughness is achieved by depositing a GeO2-embedded GeBPSG layer on a substrate, annealing, selectively etching to remove GeO2, forming a container, and depositing a blanket rough polysilicon layer over the GeBPSG layer to replicate the underlying surface roughness.

Dependencies are inferred from the claim text.