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

Abstract

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.