A bit line structure and associated fabrication method are provided for a semiconductor element or circuit arrangement. The bit line structure contains a surface bit line and a buried bit line. The buried bit line is formed in an upper section of a trench and is connected to an associated first doping region via a first connection layer. A first trench filling layer, which is insulated from the buried bit line by a second trench insulating layer, is situated in a lower section of the trench.