Complete suppression of the transient enhanced diffusion of B implanted in preamorphized Si by interstitial trapping in a spatially separated C-rich layer

A method for completely suppressing the transient enhanced diffusion (TED) of boron implanted in preamorphized silicon is demonstrated. Boron is implanted in a molecular beam epitaxy (MBE) grown silicon sample that has been previously amorphized by silicon implantation. The sample is then annealed in order to epitaxially regrow the amorphous layer and electrically activate the dopant. The backflow of silicon interstitials released by the preamorphization end-of-range (EOR) damage is completely trapped by a carbon-rich silicon layer interposed by MBE between the damage and the implanted boron. No appreciable TED is observed in the samples up to complete dissolution of the EOR damage, and complete electrical activation is obtained. The method might be considered for the realization of ultrashallow junctions for the far future complementary metal-oxide-semiconductor technology nodes.