A semiconductor device and a method for fabricating the semiconductor device. The device includes: a doped semiconductor having a source region, a drain region, a channel between the source and drain regions, and an extension region between the channel and each of the source and drain regions; a gate formed on the channel; and a screening coating on each of the extension regions. The screening coating includes: (i) an insulating layer that has a dielectric constant that is no greater than about half that of the extension regions and is formed directly on the extension regions, and (ii) a screening layer on the insulating layer, where the screening layer screens the dopant ionization potential in the extension regions to inhibit dopant deactivation.