Progress in integrated circuit (IC) technology has been achieved by reduction in the total area of individual transistors, resulting in an increase of speed accompanied by dramatic increase in density of device and interconnect integration. However, the metal oxide semiconductor field-effect transistor (MOSFET) has physical limits for reduction due to both short-channel effects, and the size of the area taken up by source and drain contacts and doping wells. To overcome these limits and to realize even smaller transistors, a device based on a novel operating principle is required. Furthermore, the introduction of high-k dielectrics and metal gates renders obsolete one of the key elements of Si technology scaling, the thermal growth of silicon dioxide as the gate insulator. A revolutionary non-Si based transistor might hence have a real shot at replacing CMOS technology.
The proposed metal oxide tunnel transistor (MOTT) is a device in which the tunnel probability through an insulating layer is modulated by a gate electrode. Source and drain of the device are metallic and no semiconductors are required in the process. This means that the source and drain contact areas are minimized and that no short channel effects can exist. High speed operation is expected since no minority carriers are involved. Furthermore the transistor can be grown on flexible substrates, and it is imaginable that three-dimensional circuits can be developed.