Suppression of the tunneling effect by shallow junctions in field-effect transistor

We study the quantum wave transport in nanoscale field-effect transistors. It has been shown that the tunneling effect between the source and the drai n in an ultra-short channel transistor significantly degrades the control o f the drain current by the gate. However, the tunneling effect is suppresse d by reducing the depth of the source and drain junctions which is designat ed to suppress the short-channel effects concerning the cut-off characteris tics of the field-effect transistor. The reduced junction depth confines th e carriers in the direction (gamma-direction) perpendicular to the transpor t direction (x-direction). The matching of gamma-direction wavefunctions at regional boundaries suppresses the tunneling effect and normal FET current -voltage characteristics has been obtained, which explains theoretically th e successful fabrication of nanoscale field-effect transistors. (C) 1999 Ac ademic Press.