Atomic Displacement Effects in Neutron Transmutation Doping

Abstract

The production of defects in silicon by neutron irradiation and the effects of subsequent thermal annealing are reviewed for their impact on neutron transmutation doping. Recoiling atoms from fast neutron interactions are the dominant contribution to the energy available for producing atomic displacements. Energy deposition considerations indicate that defect clusters are created but amorphous zone formation is highly unlikely. Extensive defect reordering occurs at room temperature with resultant vacancy- vacancy, vacancy-impurity, interstitial-insterstitial, and interstitial-impurity interactions. Many irradiation-produced defects have been characterized and identified for annealing temperatures 500°C, and to understand the interaction processes in their formation. Although the concentrations of residual defects are relatively low, these residual defects are of primary importance for neutron transmutation doping and also for ion implantation.