Measuring dopant concentrations in compensated p-type crystalline silicon via iron-acceptor pairing

We present a method for measuring the concentrations of ionized acceptors and donors in compensated p-type silicon at room temperature. Carrier lifetime measurements on silicon wafers that contain minute traces of iron allow the iron-acceptor pair formation rate to be determined, which in turn allows the acceptor concentration to be calculated. Coupled with an independent measurement of the resistivity and a mobility model that accounts for majority and minority impurity scatterings of charge carriers, it is then possible to also estimate the total concentration of ionized donors. The method is valid for combinations of different acceptor and donor species. (C) 2008 American Institute of Physics.