Interfacial Reactions of Ni, Si/Ni and Ni/Si Films on (100)GaAs

The interfacial reactions of Ni, Si/Ni and Ni/Si films on GaAs have been investigated by X-ray photoelectron spectroscopy. In the 450°C-annealed Ni/GaAs system, the interfacial reaction occurred extensively, resulting in formation of the Ni-Ga, Ni-As and Ni-Ga-As compounds. In the annealed Si/Ni/GaAs system, the reaction began at both the Si/Ni and Ni/GaAs interfaces. The Ni silicide formed by intermixing at the Si/Ni interface play a role as a barrier film in preventing out-diffusion of the Ga and As atoms from the Ni/GaAs interface. On the other hand, in the Ni/Si/GaAs system, annealing produced intermixing at the Ni/Si interface but hardly any interfacial reaction at the GaAs substrate.