The electrical conductivity of n-type silicon depends on the doping concentration which varies from1022-1026/m³ at a given temperature 3000K where ionized impurity scattering is the dominant scattering mechanism. This work founds that the electrical conductivity of n-type silicon increases as the electron concentration increases as the result of doping. When the electron concentration increases, the Fermi energy increases from the result of the Fermi level increment.