On the Measurement of Impurity Atom Distributions in Silicon by the Differential Capacitance Technique

A mathematical analysis is presented on the measurement of an impurity atom distribution in silicon by the differential capacitance technique. This analysis shows some inherent errors that can arise when the technique is applied to material containing a small impurity atom density. An important conclusion is that the differential capacitance measurement establishes the distribution of majority carriers, rather than the distribution of impurity atoms; therefore this measurement technique is applicable only in regions of semiconductor material exhibiting charge neutrality.