  Germanosilicides, especially those formed on compressive substrates, are less
stable than silicides against agglomeration. By studying the solid-state
reaction of Ni thin film on strained Si0.8Ge0.2(001), we show that nickel
germanosilicide is different from nickel silicide and nickel germanide in
several respects: the grains are smaller and faceted, the groove angle is
sharper, and dealloying takes place. The germanium out-diffusion creates a
stress in the film which favors grooving and agglomeration.
