Nickel germanide formation on condensed Ge layer for Ge-on-insulator device application

As an effort for realizing a germanium-on-insulator (GOI) device, a method of fabricating a GOI substrate and a technique for forming nickel germanide by a multistep annealing method are presented in this paper. A GOI substrate was fabricated by a germanium condensation technique, that involves a new approach of SiGe epitaxial growth on a silicon-on-insulator (SOI) substrate at a certain modulating gas ratio (Si₂H₆/GeH₄). From the results of atomic force microscopy (AFM), X-ray diffractometer (XRD) and Raman spectroscopy measurements, it was found that this technique can be practically used for GOI substrate fabrication. The novel nickel germanide formation technique with the multistep annealing method was also studied on a condensed GOI layer. A NiGe layer with a low sheet resistance (6.5 Ω/sq.) was obtained at 500°C. This result confirmed that this method is suitable for nickel germanide formation for fabricating GOI MOSFETs with low source/drain resistances. These technologies are applicable to GOI device fabrication.