Authors: K. Matsuda, H. Nakatsuji and Y. Kamakura
Affilation: Naruto University of Education, Japan
Pages: 186 - 189
Keywords: strain, density-of-state, silicon, hole
Recently, strained-Si on Si1-xGe_x subtrate attracts considerable attention so as to enhance the carrier mobility in MOSFETs. The hole transport mechanism, however, has no been completely understood yet. The most important problem this mechanism is thestraned-induced. In the present approach, we calculated the average attracts of FSDOS in strained-Si by using a non-local pseudopotential methds, The strained-Sr and Monte Carlo simulation. The strain-induced change in density-of-state (DOS) is estimated, which is comprised of two effects: the distortion of the valence band, and the splitting of heavy hole and right hole bands . The mixing ratio of the DOSs for the heavy hole and right hole bands in the latter effect is determined by Fermi distribution function including the magnitude od the splitting. The FSDOS is comprised of two FSDOSs which are caused by different scattering machanism: the intra-band scattering and the inter-band scattering. These two FSDOSs are computed by the Monte Carlo simulation. Then the mixing rate of the intra-band and inter-band phonon scattering are estimated, though the former leads no effects on the charge of the final state density-of-state. As the results, we show the band splitting plays an important role for FSDOS and the magnitude of the hole mobility is shown. We also present some approximated formulae for FSDOS by deducing from the theory of Pickus and Bir . Our results of the simulation are compared with the recent works [3,4,5].  Carl. L. Julian and F. O. Lane, Jr Change ot the Density-of-State Effective Mass of Holes in Germanium Induced by  and  One-Dimentional Strain and by  and  Uniaxial Stress, Phys. Rev. B7(2), 723 (1973).  G. L. Bir and C. E. Pickus, Symmetry and Strain-Induced Effects in Semiconductors, John Wiley & Sons, New York/Tronto 1974.  A. P. French, P. A. Besse, M. Bachtold and R. S. Popovic Simulation of the Piezo-Tunneling Effect, Tech. Proc. of the Second Intl Conf. on MSM, 419(1999).  J. R. Watling, A. Asenov and J. R. Baker, Efficient Hole Transport Model in Warpped Bands for Use in the Simulation of Si/SiGe MOSFETs, IWCE-6, 96(1998).  F. B. Bufler, Full Band Monte Carlo Simulation of Electron and Holes in Strained Si and SiGe, (Herbert Utz Verlag, Wissenchaft, 1998).