The formation of Ni germanides by magnetron sputtering and flash lamp annealing

Silicides have been widely used for CMOS devices in order to provide a stable Ohmic contact with a low contact resistivity. With the integration of Ge on Si the focus also shifted to germanides as a low resistivity contact material. In addition, ferromagnetic germanides may serve as spin injector materials for Ge-based spintronic devices. Usually, germanides have been fabricated by furnace or rapid thermal annealing in literature.

In this contribution we investigate the formation process of Ni germanides using a combination of magnetron sputtering and flash lamp annealing (FLA). Three different types of Ge served as a substrate for the deposition of the transition metal: amorphous Ge made by magnetron-sputtering on a SiO2-Si substrate, polycrystalline Ge made by magnetron-sputtering followed by FLA, and monocrystalline Ge in the form of a (100) Ge wafer. After metal deposition samples are in-situ annealed by FLA without breaking the vacuum, which triggers the formation of germanides and prevents a possible, but unwanted oxidation. In order to investigate the crystallization behavior, the structures have been characterized by Raman spectroscopy, X-ray diffraction, ellipsometry, current-voltage and Hall effect measurements.