Interstitial trapping efficiency of C+ implanted into preamorphised silicon - Control of EOR defects

The trapping of Si interstitials by C+ implantation has been quantified by following the evolution of EOR defects during thermal annealing. Si (100) n-type wafers have been preamorphised by the implantation of 150 keV Ge+ ions to a dose of 2 x 10(15) ions/cm(2) to form a 175 nm thick amorphous layer, followed by C+ implantation at 65 keV (R-p = 175 nm) to doses ranging from 3 x 10(13) ions/cm(2) to 3 x 10(15) ions/cm(2). All samples were then annealed at 1000 degrees C for 15 s. These structures have been investigated by RES, TEM and SIMS. The mean radius of the EOR loops monotonically decreases with increasing dose of C+ inns while their density increases, The number of Si self-interstitials stored in the loops also decreases with increasing carbon dose. This effect is associated with the capture of Si self-interstitials by Si-C complexes. The effective trapping efficiency of carbon is about 1.18 interstitials per carbon atom, which is consistent with values obtained from studies of B transient enhanced diffusion.