Microstructural Innovation of Ni Germanide on Ge-on-Si Substrate by Using Palladium Incorporation

In this article, thermally stable Ni germanide using palladium (Pd) incorporation is proposed for high performance germanium metal-oxide-semiconductor field-effect transistors, and a microstructural analysis of the Ni germanide is performed in depth. The proposed Pd/Ni/TiN structure exhibited a stable sheet resistance despite high temperature postgermanidation annealing of up to 500°C for 30 min. The cause of the improved thermal stability is determined to be caused by the pileup of Pd atoms at the bottom region of NiGe, which resulted in the retardation of NiGe agglomeration by the formation of PdGe or NiPdGe there.