Damage and recovery in arsenic doped silicon after high energy Si+ implantation

Electrical measurements were used to study the irradiation effects and the annealing behavior of heavily As doped silicon on insulator samples implanted with 2 MeV Si+ ions. It is found that implantation induces a strong reduction of the carrier density, which markedly depends on the concentration of As. Annealing at temperatures in the range 600-800 °C, by rapid thermal treatments or heating in furnace, showed that recovery takes place in two stages. The kinetics of the former, which should involve point defect-dopant complexes or small defect clusters, is rapid, while more stable defects demanding prolonged heating recover in the latter stage. It is concluded that these more stable defects should originate by the aggregation with an Ostwald ripening mechanism of the dopant-defect complexes and small point defect clusters, a phenomenon which competes with their annihilation. These processes, which ultimately determine the carrier density trapped in the stable defects, can also partially take place under the Si+ implantation. The effects of irradiation dose, temperature of the samples in the course of the irradiation, dopant concentration, and annealing temperature on defect structure and carrier concentration are reported and discussed.