Patent ID: 6939805

Claim:
A method for fabricating a trench capacitor having an inner capacitor electrode and an outer capacitor electrode, which comprises the following method steps: providing a substrate having a substrate surface and a trench formed therein, the trench having a trench sidewall, an upper region proximal to the substrate surface and a lower region distal from the substrate surface; forming a stop layer on the trench sidewall; depositing nanocrystallites on the stop layer to form a part of the outer capacitor electrode; subjecting the nanocrystallites to a dry-etching process, with the nanocrystallites exposed in the upper region and in the lower region of the trench, to partly remove the nanocrystallites from the trench, and thereby setting parameters for the dry-etching process causing the nanocrystallites to be removed from the upper region of the trench but to remain in place in the lower region of the trench, the dry-etching process including etching with sulfur hexafluoride and nitrogen as etching gases; and subsequently forming a capacitor dielectric in the trench; and at least partially filling the trench with a conductive trench filling forming the inner capacitor electrode.