The present invention relates to a process for realizing a connecting structure in a semiconductor substrate, and the semiconductor substrate realized accordingly. The semiconductor substrate has at least a first surface, and is foreseen for a 3D integration with a second substrate along the first surface, wherein the 3D integration is subject to a lateral misalignment in at least one dimension having a misalignment value. This process includes growing a diffusion barrier structure for preventing diffusion of elements out of a conductive layer into the rest of the semiconductor substrate, wherein a first end surface, being the most outward surface of the diffusion barrier structure and being substantially parallel to the first surface, along a direction perpendicular to the first surface and going from the substrate toward the first surface, of the diffusion barrier structure can have a length, in the direction of the lateral misalignment, the length being dependent on the misalignment value, wherein the length of the diffusion barrier structure is chosen such that in a 3D integrated structure a diffusion of elements out of a conductive layer of the second substrate is prevented in the integrated state.