An electronic device can include a substrate and an insulating structure laterally surrounded by the substrate. In an aspect, the electronic device can include a first conductive structure or an active region that is laterally surrounded by the insulating structure and the substrate. In another aspect, the electronic device can include an inductor surrounded by the insulating structure. In a further aspect, a process of forming an electronic device can include patterning a substrate to define a trench and a plurality of features, including a first feature and a second feature, within the trench; forming a first insulating layer within the trench; removing the first feature to create a first cavity; forming a second insulating layer to at least partly fill the first cavity; removing the second feature to create a second cavity; and forming a conductive or semiconductor structure within the second cavity.