In-Pile Hall Coefficient and Conductivity Measurements on Zone-Refined, p-Type Silicon

Abstract

The Hall coefficient and conductivity have been measured during pile‐irradiation for a number of zone‐refined, p‐type silicon crystals with initial resistivities of 1, 8, and 100 Ω‐cm. To supply the magnetic field for the Hall measurements, a small electromagnet was used. The conductivity of zone‐refined silicon shows much faster changes with irradiation than pulled silicon samples of equivalent resistivity. The 100‐Ω‐cm samples exhibit a monotonic nonlinear decrease of lnσ, conductivity, vs φ_f, integrated fast flux, whereas the other samples with initial Fermi levels closer to the valence band have one or two regions of linear decrease in lnσ vs φ_f before the nonlinear decrease region is observed. The Hall mobility for the 100‐Ω‐cm samples decreases and becomes negative as a result of the carrier density decreasing with irradiation. In the case of the 8‐Ω‐cm sample, the Hall mobility decreases with irradiation whereas the 1‐Ω‐cm sample shows no change in Hall mobility with irradiation up to the maximum integrated flux used in the present experiment. The origins of the dependence of lnσ on φ_f as well as the behavior of the Hall coefficient and Hall mobility with irradiation are discussed.