Thermal solid phase epitaxial growth and ion-beam induced crystallisation of Ge ion implanted layers in silicon

Solid phase epitaxial growth (SPEG) of amorphous SiGe layers in Si has been investigated. The amorphous layers were formed by 40 keV ⁷⁴Ge⁺ ion implantation in Si(100) single crystals with doses giving 22 at.% Ge at the maximum of the ion implanted distribution of Ge. SPEG of the amorphous layers was achieved by either thermal SPEG or a combination of thermal SPEG and ion-beam induced crystallisation (IBIC). The crystal quality of the layers was investigated by Rutherford backscattering spectrometry and transmission electron microscopy. Fully crystallised SiGe alloy layers were obtained by annealing in a furnace at 550°C for 60 min or at 850°C for 20 min. However, the SiGe alloy layers contain extended defects formed at the relaxation of the built-in strain in the alloy layer. When the combination of thermal SPEG and IBIC was used for the SPEG very few of these defects were formed.