Comparative study of current–voltage characteristics of Ni and Ni(Pt)-alloy silicided p+/n diodes

A comparative study of the $\mathrm{I–V}$ characteristics of $p^{+}\mathrm{/n}$ diodes silicided with a pure Ni and Ni(Pt) alloy has been performed. Higher saturation currents as well as abnormal reverse $\mathrm{I–V}$ characteristics were observed for some of the diodes which were silicided with pure Ni at 700 °C while good $\mathrm{I–V}$ characteristics were observed for other diodes. Our results show that the forward current in the diodes with good $\mathrm{I–V}$ characteristics is dominated by electron diffusion in the $p^{+}$ region. For diodes with higher saturation currents, it has been concluded that both forward and reverse currents in these diodes are dominated by the current following through Schottky contacts that are formed due to inadvertent penetration of NiSi spikes through the $p^{+}$ region into n region. The formation of Schottky contact was not observed in diodes silicided with a Ni(Pt) alloy, providing a clear evidence of enhanced thermal stability of Pt containing NiSi.