Growth kinetics of palladium germanides Pd2Ge and PdGe on single-crystal and evaporated germanium

The rate of germanide formation and the composition of the resulting compounds were investigated when thin (100 -250 nm) Pd films, vacuum evaporated onto various Ge substrates, were annealed at 170-270°C for 10 min to 27 h. Both phases Pd2Ge and PdGe were observed on singlecrystal and amorphous (vacuum-deposited) Ge substrates. In all cases the compound layers grow with a (time)1/2 dependence with an activation energy of 1.5 ± 0.1 eV. Moreover, the abserved value of the growth rate depends on the crystalline nature of the Ge substrate. On (111) and (100) substrates the rates are similar, and they are 3 times lower than those on amorphous substrates.