In one implementation, a chemical device is described. The sensor includes a chemically-sensitive field effect transistor including a floating gate structure having a plurality of floating gate conductors electrically coupled to one another. A conductive element overlies and is in communication with an uppermost floating gate conductor in the plurality of floating gate conductors. The conductive element is wider and thinner than the uppermost floating gate conductor. A dielectric material defines an opening extending to an upper surface of the conductive element.