Effect of Germanium Doping on Thermal Evolution of Neutron Irradiation Induced Defects in Czochralski Si

摘要

In this paper, the impact of germanium (Ge) doping on thermal evolution of neutron-induced defects in Czochralski (CZ) silicon has been investigated. It is found that more vacancy-oxygen (VO) defects are generated in Ge-doped Czochralski (GCZ) silicon after fast neutron irradiation. This is ascribed to the promoted vacancy production and retarded vacancy annihilation caused by the large-sized Ge atoms, which lead to an increased equilibrium vacancy concentration and VO complex generation. FTIR measurements found the IR bands of vacancy-oxygen-related complexes in GCZ silicon almost copy their counterparts in CZ silicon, which implies that Ge-doping has little influence on the final states of the evolution of VO complexes. This is also verified by the variations of interstitial oxygen concentrations in CZ and GCZ silicon after isothermal annealing at 800 °C for up to 144 h. However, the evolution process may be somewhat retarded in GCZ silicon, which is caused by the continuous vacancy trapping and releasing.