Field-effect transistor device or sensor for sensing ions, molecules or biomarkers in a fluid

The present disclosure concerns a Field-Effect Transistor device or sensor comprising at least one drain region, at least one source region, at least a channel region, at least a first gate connected to the channel region, at least one stack comprising at least one metal layer or metal extension and at least one via layer or via extension; or a plurality of alternating (i) metal layers or metal extensions and (ii) via layers or via extensions, at least one second gate or second layer connected to the at least one first gate by the at least one stack, the at least one second gate or second layer permitting sensing of ions, and/or molecules and/or biomarkers, and at least one microfluidic channel or structure connected to or provided on the at least one second gate or second layer.