Free carrier absorption in heavily doped silicon layers

The standard parametrization of free carrier absorption in silicon predicting a linear dependence of the absorption on carrier concentration is revised, finding that due to several simplifications, it is only applicable up to carrier densities of about 3x10(16) cm(-3). A parametrization applicable for both p- and n-type silicon and for doping densities as high as 10(21) cm(-3) is introduced. Using this parametrization, considerably better agreement between the emitter sheet resistance of diffused layers measured by IR transmission and electrical measurements is found, proving the applicability; of the enhanced model even for heavily doped layers. Additionally; parameters for the dependence of the refractive index of silicon on doping concentration are given. (C) 2004 American Institute of Physics.