Characterization of thermal stability of Ni(SiGe)/n-SiGe contact formed by isothermal annealing

The contact NiSiGe/SiGe was formed on n-type epitaxial Si_0.84Ge_0.16 by isothermal annealing at 550°C for different time durations. Thermal stability of the contact was characterized by different methods. Material characterizations show that NiSiGe suffers from agglomeration issue while keeping in the mono-germanosilicide phase under the thermal budget in the experiment. The Schottky contact properties of NiSiGe on n-SiGe were evaluated by current-voltage (I-V) technique at room temperature. The contact shows a reduced Schottky barrier height (SBH) with a continuously increased ideality factor and leakage current with the increase of annealing time, indicating thermal degradation of the contact quality. The results show that besides material analysis, electrical measurement is also a sensitive and supplemental way to characterize the thermal stability of Ni germanosilicide film.