Synthesis and characterization of transition-metal germanides

Si was sufficient to fulfil the requirements of microelectronic industry for more than five decades. Further progress based on the miniaturisation of transistors is challenging. Therefore new materials and concepts are considered for the next generation of nanoelectronics. In this work, we present the formation of transition-metal germanides epitaxially grown on Ge wafer. Those materials have great promise for both the ohmic contacts to n-type Ge with extremely low specific contact resistivity and spintronics. The transition-metal germanides are synthesized by metal sputtering on Ge followed by millisecond range flash lamp annealing which is suitable for larger-area fabrication and compatible with CMOS technology. On one hand, orthorhombic NiGe whose contact resistivity is only around 1.2×10-6 Ω cm2, is beneficial for achieving high-performance Ge-based nano-electronic devices. On the other hand, cubic FeGe with B20 phase is a Skyrmion-carrier material attractive for spintronics. In summary, the epitaxial transition-metal germanides materials can be obtained by a novel epitaxial approach which provides insight to their technological usage.