P-type ultra-shallow junctions were widely fabricated using Ge pre-amorphization prior to ultralow-energy B implantation. However, for future technology nodes, issues arise when bulk Si was supplanted by Si-on-insulator. An understanding of the effect of the buried Si/SiO2 interface on defect evolution, electrical activation, and diffusion was needed in order to optimize the pre-amorphization technique. In the present study, B was implanted in Ge pre-amorphized Si and Si-on-insulator wafers with different pre-amorphizing implant conditions. Subsequent to implantation an isothermal annealing study of the samples was carried out. Electrical and structural properties were measured by Hall-effect and secondary-ion-mass spectroscopy techniques. The results showed a variety of interesting effects. For the case where the Ge pre-amorphization end-of-range defects were close to the buried oxide interface, there was less dopant deactivation and less transient-enhanced diffusion, due to a lower interstitial gradient towards the surface.

Effect of Buried Si/SiO2 Interface on Dopant and Defect Evolution in Pre-Amorphizing Implant Ultra-Shallow Junction. J.J.Hamilton, B.Colombeau, J.A.Sharp, N.E.B.Cowern, K.J.Kirkby, E.J.H.Collart, M.Bersani, D.Giubertoni: Journal of Vacuum Science & Technology B, 2006, 24[1], 442-5