Size and Orientation Effects on the Kinetics and Structure of Nickelide Contacts to InGaAs Fin Structures.

ABSTRACT

The rapid development of ultrascaled III-V compound semiconductor devices urges the detailed investigation of metal-semiconductor contacts at nanoscale where crystal orientation, size, and structural phase play dominant roles in device performance. Here, we report the first study on the solid-state reaction between metal (Ni) and ternary III-V semiconductor (In0.53Ga0.47As) nanochannels to reveal the reaction kinetics, formed crystal structure, and interfacial properties. We observe a size-dependent Ni surface diffusion dominant kinetic process that gradually departs to a volume diffusion process as the Fin width increases, as properly depicted with our Fin-specific growth model. The interfacial relationship was found to be Ni4InGaAs2 (0001) ∥ In0.53Ga0.47As (111) with a single Ni4InGaAs2 phase whose [0001] axis exhibit a peculiar rotation away from the nickelide/InGaAs interface due to surface energy minimization. This crystalline interfacial relationship is responsible for introducing a uniaxial height expansion of 33% ± 5% in the formed nickelide segments. Further, the nickelide formation resulted in both in-plane and out-of-plane compressive strains in the Fin channels, significantly altering the In0.53Ga0.47As energy band-edge structure near the interface with a peak bandgap energy of ∼1.26 eV. These timely observations advance our understanding and development for self-aligned contacts to III-V nanochannels and for engineering new processes that can maximize their device performance.