Abstract
By modifying the graphic method proposed in Jpn. J. Appl. Phys. 35 (1996) L555, the author aims to evaluate the densities and energy levels of impurities with two kinds of close energy levels. Using the temperature dependence of the majority-carrier concentration n(T), the function n(T) exp (E ref/k T)/k T is defined, where k is the Boltzmann constant and E ref is a newly introduced parameter. The densities and energy levels of the impurities can be evaluated from the peaks of this function. Even in Si with two donors (Sb and P), it is found that the densities and energy levels of the two donors can be evaluated accurately.