SiC Precipitate Formation During High Dose Carbon Implantation Into Silicon

Abstract

The formation of SiC precipitates during the high-dose implantation of carbon ions into Si(100) is studied by means of TEM for implantation conditions, which are suitable for the ion beam synthesis of buried SiC layers in silicon. It is observed that in crystalline silicon nm-sized epitaxially oriented 3C-SiC precipitates are formed which are almost identical in size, nearly independent of the depth and dose (4 - 9 ×10¹⁷ C⁺/cm²). With increasing dose, it is mainly the density of precipitates which increases. Amorphization of the silicon host lattice leads to depth intervals with a strongly decreased density of oriented crystalline SiC precipitates. The irradiation induced formation of larger randomly oriented SiC crystallites is observed to occur in amorphized regions after prolonged implantation. Both the irradiation induced destruction and formation of SiC precipitates contribute to the generation of a nearly box-shaped precipitate density distribution at doses near the stoichiometry dose.