INFLUENCE OF THE DOPING ELEMENT ON THE ELECTRON-MOBILITY IN N-SILICON

We present a theoretical approach to study the dependence of the elect ron mobility on the dopant species in n-doped silicon under low electr ic fields. The electron charge distribution of the impurities is calcu lated by the Thomas-Fermi theory using the energy functional formulati on. Ionized impurity scattering has been treated within the Born appro ximation. Our model accounts for degenerate statistics, dispersive scr eening and pair scattering, which become important in heavily doped se miconductors. The dielectric function is accurately approximated by a rational function. A new expression for the second Born amplitude of a Yukawa-like charge distribution is derived, which now depends on the atomic and electron numbers of the impurity ion. Monte Carlo simulatio ns including all important scattering mechanism have been performed in the doping concentration range from 10(15) to 10(21) cm(-3). The agre ement with experimental data is excellent. The results confirm the low er electron mobility in As-doped silicon in comparison to P-doped sili con. (C) 1998 American Institute of Physics.