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

We investigated the rate of germanide formation and the composition of the resulting compounds when thin (1000–2500 A) palladium films, vacuum evaporated onto various germanium substrates, were annealed at temperatures from 170 to 270°C for 10 min to 27 h. Both phases, Pd2Ge and PdGe, were observed on single-crystal and amorphous (vacuum-deposited) germanium substrates. In all cases the compounds layers grow with a (time) 1 2 dependence and with an activation energy of 1.5 ± 0.1 eV. Moreover the absolute value of the growth rate depends on the crystalline nature of the germanium substrate. On (111) and (100) substrates the rates are similar and they are three times lower than those on amorphous substrates.