Surface roughness scattering model for arbitrarily oriented silicon nanowires

Abstract

We present an extension of the unscreened generalized Prange-Nee term used to calculate the surface roughness (SR) limited mobility in arbitrarily oriented square nanowires. The presence of non-diagonal terms in the effective mass tensor is responsible for an additional term not considered in previous studies. We assess the impact of such a modification on the SR limited mobility and on the total mobility (SR and phonon scattering are considered) for devices with different orientation and size. We show that this impact is more relevant for small devices, where the SR plays an important role, even at low inversion charge.

One-dimensional multi-subband Monte Carlo simulation of charge transport in Si nanowire transistors

“…Figure 7 illustrates how the impact of surface roughness scattering is more pronounced at higher sheet densities, and varies from one width to another, in agreement with published data [2]- [6]. Figure 8 shows the phonon-scattering limited mobility of square, circular, and elliptical nanowires, for different orientations, as a function of the cross section area.…”

“…Considerable work has been carried out to evaluate the mobility of Si nanowires, relying mainly on the KuboGreenwood formalism [2]- [4], and to a lesser extent on Monte Carlo and other 1D Boltzmann equation solvers [5], and atomistic simulation methods [6]. However, more work is needed to evaluate the performance potential of NWTs with silicon and alternative material channels at the scaling limit.…”

Influence of the back-gate bias on the electron mobility of trigate MOSFETs

“…Both SR and CO scattering mechanisms are implemented taking into account the tensorial dielectric screening [8], while the phonon interactions remain unscreened. The scattering mechanisms are introduced as described in [8], except for the SR, calculated as in [10], with ∆ sr = 0.5nm and L sr = 1.5nm. The surface charge value employed (N it = 4 × 10 12 cm −2 ) is similar to that used in [11], where such a high value is needed to fit the experimental results.…”

Mobility of Circular and Elliptical Si Nanowire Transistors Using a Multi-Subband 1D Formalism

“…We adopt the Kubo-Greenwood (KG) formalism [12]- [14], while accounting for the realistic band structure of the NWTs by accurately extracting the effective masses from tight-binding band-structure simulations. This strategy delivers reliable mobility values at low-field near-equilibrium conditions and in devices with strong confinement effects [15].…”