DEPENDENCE OF ELECTRON-MOBILITY ON DOPED IMPURITIES

The dependence of electron mobility on doped impurities was investigated. Analytical expressions of the momentum relaxation cross section and the electron mobility in n- and p-doped silicon for electron-impurity scatterings have been derived. Our approach involved the application of a screened scattering potential based on a charge density distribution for impurity ions in the semiconductor. This distribution was determined by the variational statistical method. Calculated results showed that ionized acceptor impurities in silicon scattered electron carriers less strongly than did ionized donor impurities. They also showed that majority electron mobility in n-type silicon was less than minority electron mobility in p-type silicon. These were consistent with experimental observations.