PRECIPITATION STUDIES IN OXYGEN-RICH AND NITROGEN-RICH SILICON FORMEDBY HIGH-DOSE IMPLANTATION

Using ion beam synthesis and high temperature annealing, substoichiome tric buried layers rich in oxygen or nitrogen were produced and invest igated by XTEM. With increasing annealing temperature in the range 100 0-1250 degrees C, precipitates of silicon dioxide and silicon nitride are formed. Their mean size and distribution within the buried damage layer depends on the annealing temperature. At 1100 degrees C, precipi tates of comparable size homogeneously distributed throughout the buri ed layer were formed. The impact of this finding on thermodynamical mo delling of buried layer systems after high dose implantation and annea ling is discussed. A technique using SEM of bevelled silicon samples a fter preferential etching to perform precipitation studies is reported .