Electron microscopic imaging of an ion beam mixed SiO2/Si interface correlated with photo‐ and cathodoluminescence

Abstract

AbstractEnergy filtered transmission electron microscopy (EFTEM), scanning transmission electron microscopy (STEM) imaging, and electron energy loss spectroscopy (EELS) of a thin 28 nm SiO2 layer on Si substrate implanted by Si+ ions with an energy of 12 keV are reported. The maximum concentration of implanted Si+ ions is located near the SiO2–Si interface region leading there to an ion beam mixed gradual SiOX (2 ≥ x > 0) buffer region, which is even extended into the Si substrate by atomic collisions (knocking‐off and knocking‐on processes) during ion implantation. Thus, the width of this SiOX buffer layer amounts to about 30 nm extended from 10 to 40 nm depth.The SiOX profile is demonstrated by the above given electron microscopic and spectroscopic methods. Thermal annealing leads to partial phase separation from SiOX1 to SiOX2 with x2 > x1 and silicon precipitates (partially nc‐Si) changing the photo‐ (PL) and cathodoluminescence (CL) spectra especially in the near IR‐region, probably, due to the formation of Si nanoclusters and associated quantum confinement effects.