Abstract: Methods of forming semiconductor devices including an air gap extending through at least one metal layer, and the semiconductor device so formed, are disclosed. The air gap has a lower portion that contacts a silicide layer over a gate body of a transistor gate and has an inverted T-shape over the gate body. The air gap reduces the capacitance between a transistor gate in a device layer and adjacent wires and vias used to contact the source and drain of the transistor.