Density of ultrathin amorphous silicon and germanium sublayers in periodic amorphous multilayers

Abstract

We have applied high-resolution x-ray-diffraction and Rutherford-backscattering measurements on periodic amorphous multilayer structures to measure individual sublayer densities in ultrathin layers. Multilayers discussed here are composed of \ensuremath{\approxeq}5 nm hydrogenated amorphous-silicon sublayers layered with 5-nm hydrogenated amorphous-germanium sublayers. Amorphous Si and Ge in sublayers have densities of 0.98\ifmmode\pm\else\textpm\fi{}0.04 and 0.96\ifmmode\pm\else\textpm\fi{}0.03 times that of the respective crystals. These densities are close to those of the as-grown bulk amorphous materials.