An integrated microelectronic device is formed from a substrate having a first side and a second side and including a doped active zone (2) in the first side of the substrate. A circuit component is situated in the doped active zone. A through silicon via extends between the second side and the first side, the via being electrically isolated from the substrate by an insulating layer. A buffer zone is situated between the insulating layer and the doped active zone. This buffer zone is positioned under a shallow trench isolation zone provided around the doped active zone. The buffer zone functions to reduce the electrical coupling between the through silicon via and the doped active zone.