Initial stages of iridium-semiconductor compound formation and the interface atomic structures: A field ion microscope study

Abstract

The early stages of formation of thin layers of IrSi and IrGe on clean Ir surfaces and the interface atomic structures have been studied in the field ion microscope. Distinctive stages of growth of Ir-silicide have been observed. In the earliest stage, two atomic layers of silicide are formed on the Ir(001) plane. Atomically resolved images show a structure resembling the C(2×2) overlayer structure of the substrate, which we believe to have the (011) Ir-layer structure of the (011) plane of IrSi crystal. In the second stage, the (2×1) image structure observed on the Ir(011) is identified to be the Ir-layer of the IrSi(001) fundamental planes. Formation of IrGe on the Ir(001) is similar to the earliest stage of silicide formation. We believe that the ordered interface atomic structures we have observed with the FIM should also be observable at flat interfaces with conventional techniques.