Defects in neutron transmutation doped silicon studied by positron annihilation lifetime measurements

Neutron transmutation doping of n-type silicon was obtained by irradiating the samples with thermal neutrons in order to create P atoms. Positron lifetime measurements were carried out and the evolution of the induced defects was studied by thermal annealing of the samples. The annealing out of the divacancy was seen between 200 and 350 °C. Around 700 °C large vacancy clusters (containing about eight vacancies) are formed. All the defects are annealed above 800 °C.