Interfacial Defects Induced by Silicidation and Effects of H-Termination at Metal/Silicon Contacts

Abstract

ABSTRACTWe have investigated crystallographic structures and electrical properties at the interfaces of transition metals such as Ti, Zr, Hf and V and Si(100), from the viewpoint of an application to ohmic contacts in future ULSI's with low contact resistivity and high reliability. We have achieved very low contact resistivities of 3−5×10−8 Ωcm2 for Zr/ and Hf/n+-Si(100) contacts and 1−2×10-7 Ωcm2 for p+-Si at 400–600°C. It is found that the silicidation reaction in this temperature range brings about the formation of deep levels associated with vacancies in Hf/Si and with metal atoms in V/Si. This difference is considered to be related to that in the silicide formation process between these systems. Furthermore, an anomalous electrical characteristics observed for Hf/p-Si contacts has been found to be markedly improved by using a H-termination treatment of Si surfaces.