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

Abstract

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.