Fabrication method for a trench capacitor having an insulation collar which on one side is electrically connected to a substrate via a buried contact, in particular for a semiconductor memory cell, and corresponding trench capacitor

Abstract

Fabrication method for a trench capacitor having an insulation collar which on one side is electrically connected to a substrate via a buried contact, in particular for a semiconductor memory cell, and corresponding trench capacitor The present invention provides a fabrication method for a trench capacitor having an insulation collar (10; 10a, 10b) in a substrate (1), which on one side is electrically connected to the substrate (1) via a buried contact (15a, 15b), comprising the steps of: providing a trench (5) in the substrate (1) using a hard mask (2, 3) with a corresponding mask opening; providing a capacitor dielectric (30) in the lower and middle trench regions, the insulation collar (10) in the middle and upper trench regions and an electrically conductive filling (20) at least as far as the top side of the insulation collar (10), with the top side of the insulation collar (10) being at a distance from the top side (OS) of the substrate (1); causing the electrically conductive filling (20) to recede to below the top side of the insulation collar (10); on one side, forming an insulation region (IS; IS1, IS2) with respect to the substrate (1) above the insulation collar (10); on the other side, forming a terminal region (KS; KS1, KS2) with respect to the substrate (1) above the insulation collar (10); providing an interface layer (100) of a transition metal nitride on the terminal region (KS; KS1, KS2); and forming the buried contact (15a, 15b) by depositing and etching back a conductive filling (70). The invention also provides a corresponding trench capacitor.

Dependencies are inferred from the claim text.