Peculiarities of changes in electron hall mobility in dependence of measuring temperature in n-type silicon irradiated with protons

There are investigated zone-melting n-Si crystals with room temperature electron concentration of 6×10¹³ cm^-3. The samples were irradiated by protons with energy of 25 MeV at the temperature of 300 K. The Hall measurements were conducted in the temperature range 77-300 K. Studies have shown that irradiation with protons leads to a sharp increase in the Hall mobility of electrons. This should be associated with the formation in a crystal in addition to point secondary radiation defects, nanoscale clusters of interstitial atoms with high relatively to matrix conductivity, so-called ''metallic'' inclusions. The reducing in electron Hall mobility after annealing at 110℃ is explained by the appearance of impurity-defect shells around ''metallic'' inclusions. After such a low-temperature heat treatment secondary radiation defects with low thermal stability, including a certain part of the E-centers, are annealed. Formed in this process non-equilibrium vacancies tend to the ''metallic'' inclusions of interstitial atoms and create around them a defective shell, which consists of A- and E-centers, divacancies V ₂, etc. These defects are charged at different temperatures and thus ''metallic'' inclusion periodically - depending on the filling by electrons radiation defects and the electrostatic interaction forces between them - become ''dielectric'' (i.e., with low relatively to matrix conductivity), i.e. opaque to electrons, what leads to the formation of the minima on the electron Hall mobility temperature-curve. (author)