Donor States in Highly Compensated Silicon, as Elucidated by Electron Spin Resonance Experiment

Abstract

The electron spin resonance experiment was performed on phosphorus donors in compensated n-type silicon in the temperature range of 1.5 K to 4.2 K, using the microwave of 46 GHz. From the comparison of the peak shifts of the central lines in highly compensated samples and in uncompensated ones, the average local density of donor electrons were obtained in highly compensated samples, whose magnitude was rather close to N_D than N_D−N_A. This result is interpreted in terms of a simple model that the donor electrons are mostly located outside the critical spheres centred at each negatively charged acceptor as a result of Coulomb repulsion between the donor electrons and the charged acceptors, as first considered by Mott and Davis. The temperature dependence of the peak shift of the central line and the line broadening are also discussed.