an integrated circuit includes an utbox insulating layer under and plumb with first and second electronic components , and corresponding ground planes and oppositely - doped wells made plumb with them . the wells contact with corresponding ground planes . a pair of oppositely doped bias electrodes , suitable for connecting corresponding bias voltages , contacts respective wells and ground planes . a third electrode contacts the first well . a first trench isolates one bias electrode from the third electrode and extends through the layer and into the first well . a second trench isolates the first bias electrode from one component . this trench has an extent that falls short of reaching an interface between the first ground plane and the first well .