An integrated circuit device comprising:

• a body of a first solid material having an upper surface and a major bottom surface;
• a pocket of a second solid material having a top surface and a side surface, and a bottom surface which contacts a selected portion of said upper surface on said body;
• said first and second solid materials being so selected as to form, where said pocket contacts said body at said selected portion of said upper surface, an electronic interfacial barrier which is substantially conductive under an applied bias of at least one selected polarity; and
• a solid electrically insulating region which meets said barrier and adjoins both said body and at least a line on said side surface of said pocket;
• wherein at least a part of said solid electrically insulating region comprises nitrogen located at least below the level of said electronic interfacial barrier.