A semiconductor device may include a substrate having a source region and a drain region, and a gate arranged over the substrate and between the source region and the drain region. A first interlevel dielectric (ILD) layer may be at least partially arranged over the substrate and the gate. A conductive field plate may be arranged over the first ILD layer. At least one drain contact may extend through the first ILD layer over the drain region and may be coupled to the conductive field plate. A drain captive structure may be disposed in the first ILD layer and adjacent to the drain region, the drain captive structure having a trench comprising an air gap, wherein the drain captive structure is laterally spaced apart from sidewalls of the gate.