Physics of Carrier Backscattering in One- and Two-Dimensional Nanotransistors

The physics of carrier backscattering in 1-D and 2-D transistors is examined analytically and by numerical simulation. An analytical formula for the backscattering coefficient is derived for elastic scattering in a 1-D channel. This formula shows that the critical length for backscattering is somewhat longer than the kT length, and it depends on the shape of the channel potential profile. For inelastic scattering, Monte Carlo (MC) simulations show that the critical length is related to the phonon energy. The MC simulations also show that although the scattering physics in 1-D and 2-D transistors is very different, the overall backscattering characteristics are surprisingly similar. For an elastic process, this similarity is due to the compensating effects of the scattering rate and the fraction of scattered carriers, which contribute to the backscattering coefficient. For an inelastic process, the critical length is determined from the phonon energy for both 1-D and 2-D channels.