First phase to form during cobalt germanidation

The first systematic study for the first phase to form during cobalt germanidation was conducted. Hexagonal β-Co5Ge3 was the first phase to form in case of cobalt germanidation on (100) Ge. This phase formed at a temperature as low as 227 °C. Monoclinic CoGe was experimentally shown to be the second phase to form at the same temperature. Our results are contrary to the previous reports suggesting monoclinic CoGe to be the first phase to form. This is mainly due to the experimental setup that was designed to detect all forming phases: in-situ XRD monitoring at constant low temperature long time anneals of 24–48 h. We also report for the first time that both β-Co5Ge3 and monoclinic CoGe phases that formed during cobalt germanidation were highly ordered partial epitaxial crystal orientations.