A field effect transistor (FET), integrated circuit (IC) chip including the FETs and a method of forming the FETS. Each FET includes a device gate along one side of a semiconductor (e.g., silicon) fin and a back bias gate along an opposite of the fin. Back bias gate dielectric differs from the device gate dielectric either in its material and/or thickness. Device thresholds can be adjusted by adjusting back bias gate voltage.