A silicon-on-insulator device has a localized biasing structure formed in the insulator layer of the SOI. The localized biasing structure includes a patterned conductor that provides a biasing signal to distinct regions of the silicon layer of the SOI. The conductor is recessed into the insulator layer to provide a substantially planar interface with the silicon layer. The conductor is connected to a bias voltage source. In an embodiment, a plurality of conductor is provided that respectively connected to a plurality of voltage sources. Thus, different regions of the silicon layer are biased by different bias signals.