Formation of ternary Ni-silicide on relaxed and strained SiGe layers

Abstract

Ni germanosilicide formation on Si1−xGex layers with different elastic strain was investigated by sheet resistance measurements and cross-sectional transmission electron microscopy. Ni–Si–Ge silicide layers with low resistivity were obtained by depositing 20 nm Ni with an 8 nm Ti cap on the Si1−xGex layers and rapid thermal annealing within the temperature range of 400–500 °C. The sheet resistance and the thermal stability of the silicide layers depends on the elastic strain of the SiGe layer. Best uniformity of the silicide layers was obtained on relaxed SiGe layers. High strain produces rough silicide layers. Strain relaxation was observed in initially pseudomorphically strained Si0.73Ge0.27 layers during silicidation at 600 °C.