The effect of transition region on the direct tunneling current and Fowler-Nordheim tunneling current oscillations in ultrathin MOS structures

The effects of transition region on direct tunneling and Fowler-Nordheim (FN) tunneling in ultrathin metal-oxide-semiconductor field transistors are investigated by numerical analysis. Direct tunneling current in ultrathin gate oxide is shown to increase with the width of transition region. The applied voltage across the oxide at the maximum and minimum of FN tunneling current oscillations is observed to increase with the width of the transition region, and its relative increase also strongly depends on the width. Furthermore, the amplitude of FN tunneling current oscillations descends with the width of transition region, however, its attenuation factor trends to increase with the width. Usually the amplitude and its attenuation factor decrease with the ordinal number of current oscillation increasing. So the effect of the transition region on FN tunneling current oscillations may be used to extract the information about the transition region. (C) 2002 Elsevier Science Ltd. All rights reserved.