Abstract: A fabrication method is disclosed that includes: forming a first metal layer over first and second semiconductor structures; forming a first patterned photolithographic layer with an opening that exposes a portion of the first metal layer over the first semiconductor structure but not to a boundary between semiconductor structures; removing the exposed portion of the first metal layer; forming a second metal layer over the first and second semiconductor structures; forming a second patterned photolithographic layer with an opening that exposes a portion of the second metal layer over the second semiconductor structure but not to the boundary; removing the exposed portion of the first and second metal layers; wherein a barrier structure is generated between the first and second semiconductor structures that includes remaining portions of the first metal layer and a portion of the second metal layer overlying the remaining portions of the first metal layer.