Study of a 50 nm nMOSFET by ensemble Monte Carlo simulation including a new approach to surface roughness and impurity scattering in the Si inversion layer

• Published in: IEEE transactions on electron devices 2002-01, Vol.49 (1), p.125-132
• Main Authors: Formicone, G.F., Saraniti, M., Vasileska, D.Z., Ferry, D.K.
• Format: Article
• Language: English
• Subjects: Channels; Computer simulation; Devices; Impurities; Inversion layers; Monte Carlo methods; MOSFETs; Scattering; Silicon
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/16.974759

A 50 nm nMOSFET has been studied by Ensemble Monte Carlo (EMC) simulation including a novel physical model for the treatment of surface roughness and impurity scattering in the Si inversion layer. In this model, we use a bulk-like phonon and impurity scattering model and surface-roughness scattering in the silicon inversion layer, coupled with the effective/smoothed potential approach to account for space quantization effects. This approach does not require a self-consistent solution of the Schrodinger equation. A thorough account of how these scattering mechanisms affect the transport transient response and steady-state regime in a 50 nm gate-length nMOSFET is given in this paper. A set of I/sub ds/-V/sub ds/ curves for the transistor is shown. We find that the smoothing of the potential to account for quantum effects has a strong impact on the electron transport properties, both in transient and steady-state regimes. We also show results for the impact that impurity and surface-roughness scattering mechanisms have on the average velocity of the carriers in the channel and the current flowing through the device. It was found that time-scales as short as 0.1-0.2 ps are enough to reach a steady-state channel electron average velocity.