It was demonstrated that the implantation of MeV Si ions into a Si substrate could suppress boride-enhanced diffusion normally associated with a high B concentration layer. In this study, a molecular-beam epitaxially grown Si layer with a B concentration of 1021/cm3 over a 10nm region capped with 100nm Si was used as a source of boride-enhanced diffusion. A sequence of four B delta-doped layers with 100nm Si spacers was grown prior to the source layer to monitor the diffusion. Half of the sample was implanted with 1MeV Si ions at a dose of 1016/cm2, followed by annealing at 800, 900 and 1000C for different periods of time. For control samples without the MeV Si implant, boride-enhanced diffusion was observed with enhancements of around 40 while the MeV Si-implanted sample exhibited a reduced, yet non-vanishing, boride-enhanced diffusion with an enhancement of around 8 after annealing (800C, 1h). Both boride-enhanced diffusion and suppressed boride-enhanced diffusion with MeV implant exhibited transient behavior with decay after annealing for long periods of time.

Reduction of Boride Enhanced Diffusion in MeV-Implanted Silicon. L.Shao, P.E.Thompson, R.J.Bleiler, S.Baumann, X.Wang, H.Chen, J.Liu, W.K.Chu: Journal of Applied Physics, 2002, 92[10], 5793-7