Monte Carlo Study of the Coulomb Interaction in Nanoscale Silicon Devices

Effect of dynamical Coulomb interaction on junctionless transistor performance: Monte Carlo study of plasmon excitations

“…The self-consistent MC simulation predicts lower drain current, though its magnitude is not large in each gate voltage condition. This tendency is consistent with those found previously for the inversion-type FETs: 14,16 The dynamical screening taken place near the drain/source associated with the long-range Coulomb interaction between the channel electrons and electrons in the drain/source degrades drain current. A similar scenario holds true in the present case and the details of current degradation will be discussed elsewhere.…”

“…Spatial grid and time step to update the long-range electrostatic potential are chosen to be fine enough to resolve the dynamical potential modulation (collective excitation of plasma waves), as well as to reproduce the correct electron mobility under high-impurity concentrations. 15,16 Figure 1 shows the device structure introduced into our MC simulations, i.e., the JLT with the cross section of 10 Â 10 nm 2 surrounded by the metallic gate with 50 nm long. The donor concentration of Si substrate is assumed to be 10 19 cm À3 , and the thickness of gate insulator (SiO 2 ) is 0.86 nm.…”

Monte Carlo Study of Ultimate Channel Scaling in Si and In$_{\rm 0.3}$Ga$_{\rm 0.7}$As Bulk MOSFETs

“…Consequently, this starts electron interactions with intervalley nonpolar optical phonons assisted by the redistribution of electron momenta through the long-range Coulomb interaction (resulting is in excitation of plasmons in the heavily doped source and drain [9] as mentioned previously) and leads to a quick loss of electron energy and decline in their velocity in the channel region. This redistribution of electron momenta through the long-range Coulomb interaction has also been recently reported in MC simulations of nanoscaled Si double gate MOSFETs with uniformly doped S/D [28] which also included short-range electron-electron interactions [32]. However, when these slowing electrons reach the end of the gate where a very high electric fringing field is present again, they are enormously accelerated and enter the drain side with larger velocity as the injection velocity at the source.…”

“…A higher injection velocity promises a much faster switching speed which is one of the main drivers of the research into III-V MOSFETs [26], [27]. However, the ultimate question of achieving a purely ballistic transport in the transistor channel remains intriguing [28]. Therefore, we have scaled these two MOSFETS with the 25-nm gate length based on different channel materials determining different doping strategies only laterally to ultimate limit as depicted in Fig.…”

Impact of the Coulomb interaction on nano-scale silicon device characteristics

“…The previous two-dimensional MC simulations with and without the Coulomb interaction (empty marks with dotted curves) are also shown along with some experimental results (empty marks with solid curves) DG-MOSFET with L ch = 40 nm between the MC simulations under the self-consistent potential and under the fixed potential[14].…”