Thermally and ion-induced reaction between Si and binary metallic alloys

Thermally and ion-induced reactions, between Si and binary metallic alloys of PtV (solid solution), NiTa (amorphous phase), and PtTi (intermetallic compound) were investigated. Thermal annealing was carried out at temperatures of 500--700 0C. Separated binary silicides were formed in Pt-V and Ni-Ta systems, while the ternary compound of PtTiSi was observed in the Pt-Ti system. Ion irradiation was performed at temperatures of 200--440 0C. Uniform mixed amorphous layers were produced in all the three systems upon irradiation at relatively low temperatures. The difference in reactions between thermal annealing and ion mixing was attributed to the enhanced Si mobility. The mixtures of PtVSi2 and NiTaSi2 were transformed to separated binary silicides by post-annealing, but the PtTiSi2 underwent an amorphous-metastable phase transformation. It was also found that ion mixing and thermal annealing behaved similarly when ion irradiation was carried out at relatively high temperatures