Ultra low energy SIMS, XTEM and X-ray diffraction methods for the characterization of a MBE grown short period (SinGem)16 superlattices

Abstract

The structural parameters (the layer thickness, interface roughness) for a 16-period (SinGem) superlattice grown by solid source molecular beam epitaxy (MBE) on Si(001) substrates were determined by high-resolution X-ray diffraction (HRXRD), X-ray reflectivity (XRR) and cross-sectional transmission electron microscopy (XTEM). The results were compared to the data obtained by ultra-low energy secondary ion mass spectrometry (ULE SIMS) method, using a 280 eV O2+ probe at 20° to normal incidence. The differences in layer thickness values obtained from HRXRD, XRR and XTEM, ULE SIMS data, are explained in terms of significant microroughness at both the Si/Ge and Ge/Si interfaces. The n and m values were also determined by X-ray diffraction methods.