Helium implantation in silicon: detailed experimental analysis of resistivity and lifetime profiles as a function of the implantation dose and energy

In this paper, a study of the effects on both lifetime and resistivity, induced by helium implantation processes, is presented. A wide range of implantation energies (from 3.5 MeV to 5.8 MeV) and doses (from 1middot10⁸ atm/cm² to 2middot10¹¹ atm/cm²) is considered and, for each of them, the resistivity profile and the lifetime profile are measured and compared with that of the unprocessed material. Moreover, the temperature dependence of that profile is analysed in the usual operation range of power devices. Results show that a high helium dose not only reduces the recombination lifetime but significatively affects the resistivity too. The temperature dependence of the two parameters is such that they play different roles at high or low temperature