Impact of channel constrictions on the formation of multiple tunnel junctions in heavily doped silicon single electron transistors

This paper reports the study of the uncontrolled multiple tunnel junctions (MTJs) induced by the random dopants in heavily doped silicon single electron transistors (SETs). The SETs are fabricated by making dual lateral constrictions in the narrow doped silicon channel formed on a silicon on insulator substrate. The doped SETs with relatively long constriction regions invariably exhibit the MTJ characteristics. The influence of the MTJs is suppressed by tuning the Fermi level in the constriction region. Finally, we show that the formation of uncontrolled MTJs can be avoided by making extremely sharp constrictions.