Formation of Mn-germanide nanodots on ultrathin SiO2 induced by remote hydrogen plasma

Abstract

High-density Mn-germanide nanodots [MnxGe1−x (x = 0.8) NDs] with an areal dot density as high as ∼1012 cm−2 were formed on thermally grown SiO2 by exposing ∼1.0-nm-thick Mn/∼1.0-nm-thick amorphous Ge (a-Ge) bilayer stacked structures to a remote H2 plasma (H2-RP) without external heating. The germanidation reaction of the Mn/a-Ge bilayer was observed through high resolution X-ray photoelectron spectroscopy measurements. Electrical isolation among the MnxGe1−x (x = 0.8) NDs was verified from the changes in surface potential after charge injection using an atomic force microscope/Kelvin probe technique. As seen from the VHF input power and exposure time dependence of the ultrathin bilayer stacked structures, control of thickness and H-radical flux are important parameters for the high-density formation of MnGe alloy NDs induced by H2-RP.