Interfacial reactions of electroless nickel thin films on silicon

Interfacial reactions of electroless nickel thin films on blank silicon annealed at 300–900 °C have been studied by both cross-sectional and planview TEM as well as by sheet resistance measurement. Samples were prepared by depositing Ni on (0 0 1)Si substrate by electroless plating deposition followed by annealing to form a silicide. An amorphous interlayer was found in interface between electroless nickel thin films and silicon. The amorphous interlayer blocks the reaction between Ni and Si and change the silicide formation sequence. The epitaxial NiSi 2 was found on electroless plating nickel thin films on silicon at the temperature as low as 300 and 400 °C. The presence of phosphorus in the electroless Ni films and/or amorphous interlayer between electroless Ni films and Si were found to promote the formation of the epitaxial NiSi 2 at low temperature. The dominant phase was NiSi in samples annealed at 500–700 °C. The results have shown that NiSi film formed by electroless plating process has the same resistance property as the NiSi film formed by vacuum plating process. The electroless plating technique can provide a cheap and easy process for forming nickel silicide, and has potentiality of application for the electronic device industries.