Future ultra-large scale integration: Transport physics in semiconductor nanostructures

The progress in Si ULSI, and the parallel progress in GaAs LSI, has pushed the gate length in current devices toward 0.1 μm. Research laboratories have gone even further, and FETs with gate lengths as short as 20 nm have been demonstrated. It is apparent that within the next decade or so, devices with gate lengths approaching this scale will be made in the production environment. These devices are likely to be susceptible to new physical effects that are now being studied in nanostructures, or mesoscopic devices as they are usually called. The first new effect, already seen in the short-gate length devices, is tunneling through the gate depletion region. In this paper, we try to summarize the major physical effects, some approaches to studying them, and the role they may play in future industrial devices.