Herstellungsverfahren für einen Grabenkondensator mit einem Isolationskragen, der über einen vergrabenen Kontakt einseitig mit einem Substrat elektrisch verbunden ist, insbesondere für eine Halbleiterspeicherzelle

Production of a trench capacitor comprises forming a trench (5) in a substrate (1) using a hard mask (2, 3) with a corresponding opening, placing a capacitor dielectric (30) in the trench and over the mask, pouring an electrically conducting filler (20) into the trench until it is below the upper side of an insulating collar (10), exposing an insulating region (IS) of the substrate above the upper side of the collar and forming an insulating layer (70) in the trench on the insulating region, exposing a contact region (KS) of the substrate lying opposite the insulating region and forming a conducting layer (90) in the trench on the contact region by selective epitaxy, and pouring a further conducting filler (21) in the trench above the sunk conducting filler (20).