Radiation defects produced by helium implantation were used to shape profiles of Pd and Pt atoms in-diffusing (for 20min at 600 to 800C) either from surface silicide (Pd2Si, PtSi) or implanted layers. Results showed that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centres – the acceptor level of substitutional Pd (Ec−0.22eV) or Pt (Ec−0.23eV). While optimum conditions for Pt in-diffusion were about 700C, Pd gives the best results already at 600C, where it also exhibited higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by Pd and Pt, exhibited similar trade-off between the static and dynamic parameters as the diodes subjected to standard He irradiation. However, for equivalent lifetime reduction, the Pd and Pt in-diffused diodes showed much lower leakage and much higher thermal budget.

Low-Temperature Radiation Controlled Diffusion of Palladium and Platinum in Silicon for Advanced Lifetime Control. J.Vobecký, P.Hazdra: Nuclear Instruments and Methods in Physics Research B, 2006, 253[1-2], 162-6