Effect of current crowding on contact failure in heavily doped n⁺- and p⁺-silicon-on-insulator

Stability of submicron contacts under high current density has been an outstanding reliability issue in advanced Si devices. Polarity effect of failure was observed in Ni and Ni₂Si contacts on n⁺-Si and p⁺-Si. In this report, we studied the failure due to high current density in contacts to n⁺- and p⁺-silicon-on-insulator (SOI). We found similar polarity effects below certain current: the p⁺-SOI failed preferentially at the cathode, while the n⁺-SOI failed preferentially at the anode. At higher current, damage occurred at both contacts. The effect of current crowding was evident in both cases.