THE EFFECT OF IMPURITY CONTENT ON POINT-DEFECT EVOLUTION IN ION-IMPLANTED AND ELECTRON-IRRADIATED SI

We compare the defect complexes generated in crystalline Si by electro n irradiation and ion implantation, using irradiation fluences which d eposit the same total energy in nuclear collisions. Deep level transie nt spectroscopy was used to monitor both vacancy-type (e.g., divacanci es) and interstitial-type (e.g., carbon-oxygen complexes) defects prod uced on p-type Si samples. We show that identical defect structures an d annealing behavior, T less than or equal to 300 degrees C, are produ ced by both Si implantation and electron irradiation. After annealing at higher temperatures, we observe a higher residual damage in ion imp lanted samples, which is a direct consequence of the extra incorporate d ions. We demonstrate that the substrate impurity content rather than the ion cascade dominates defect formation and evolution. In high pur ity Si, B-related instead of C-related (e.g., the carbon-oxygen comple x) defects preferentially store the interstitials which escape direct recombination with vacancies, and the thermal stability of the CiOi co mplexes is decreased in Si containing low concentration of impurities. (C) 1997 American Institute of Physics.