Kinetic study of velocity distributions in nanoscale semiconductor devices under room-temperature operation

Quasiballistic electron transport in nanoscale semiconductor structures is investigated to clarify the importance of scatterings under room-temperature operation as reflected in the velocity distribution functions. The analyses are carried out for n+-n-n+ structures based on the semiclassical Boltzmann transport equation (BTE). It is shown that the number of electrons with negative velocity grows exponetially due to scatterings around the top of the electronic potential barrier in the channel region and, thus, the scatterings cannot be neglected even in nanoscale device structures. This is closely related to the mathematical structure of the BTE whose solution exhibits the boundary-layer structure