Surface crystallization of ion-implantation damaged Si₉₅Ge₅ on Si(100)

Si(100) was implanted with 80 keV Ge ions to a Si₉₅Ge₅ composition. The implanted layer (120 nm thick) was amorphous as judged by XTEM, but the valence band photoelectron spectra from this system were clearly different from earlier data on amorphous Si. Thermal regrowth of the damaged layer was found to proceed, as expected, from the damaged-undamaged interface. However, even after extended annealing at temperatures well above that required for interfacial regrowth, the surface region remained disordered (non-single crystal). The results are interpreted in terms of parallel recrystallization of the implantation-damaged layer at the interface as well as at the surface. Due to lack of a template, the latter process does not result in a single crystal.