Amorphous Ni-Mo-P diffusion barrier deposited by non-isothermal deposition

Ni-Mo-P barrier layers deposited on silicon wafers without Pd activation pretreatment were prepared using the non-isothermal deposition (NITD) method in an acidic electroless bath. The operating conditions for fabricating the Ni-Mo-P barrier layers were presented, and the effect of the pH values on the film composition, electric resistivity and thermal stability have been investigated. The thicknesses of Ni-Mo-P films are around 15-20 nm in acidic bath. Our results indicate increasing amounts of Mo and decreasing amounts of P with increasing pH. The electric resistivity decreased with increasing pH value due to the increase of the Mo content in the Ni-Mo-P film. The amorphous structure was formed at pH 3 and 4, but a quasi-amorphous structure was formed at pH 5. Based on our experimental results, the thermal stability of Ni-Mo-P film prepared at pH 4 remains stable up to 650 °C for 1 h annealing.