Characterization of Si-implanted and electron-beam-annealed silicon-on-sapphire using high-resolution electron microscopy

Silicon-on-sapphire films have been characterized by high-resolution electron microscopy at 500 kV following silicon implantation and electron beam annealing. The effect of implantation with 10¹⁵ Si/cm ² at 190 keV was to amorphize most of the 0.3-μm silicon layer, in particular breaking up the lattice defects originating from the interface. The remaining crystalline surface layer acted as a seed for the recrystallization of the film back to the interface. There was a substantial decrease in the number of lattice defects present in the silicon compared to the as-grown films, although amorphous layers varying in thickness up to 50 Å were formed at the interface. Rutherford backscattering spectrometry measurements of the film crystallinity showed good correlation with the observed microstructural changes.