Formation of Mn5Ge3 by thermal annealing of evaporated Mn on doped Ge on Si(111)

Abstract

Mn5Ge3 can be used as a ferromagnetic contact material to fabricate spintronic devices. Here, we show that Mn5Ge3 can be fabricated with a simple germanidation process by evaporating Mn on undoped and doped Ge on Si followed by a thermal annealing step to form the ferromagnetic Mn5Ge3 phase. This solid phase preparation of Mn5Ge3 is a robust process with a minor dependence on the annealing parameters. The formation of Mn5Ge3 can be realized using undoped as well as highly doped p-Ge and n-Ge with different doping levels. The interface of Mn5Ge3 is atomically sharp which leads to very low contact resistivities < 1 × 10−7 Ω cm2.