Effect of plating temperature on electroless amorphous Ni–P film on Si wafers in an alkaline bath solution

Abstract

Nickel–phosphorus (Ni–P) film was deposited by electroless process on the surface of p-type polycrystalline silicon at the temperature of 60–80 °C and pH value of 10.0. The effect of plating temperature on morphology, crystallographic structure, chemical composition and deposition rate of Ni–P film was studied. Microstructure and morphology of surface and cross section of the film were examined by a scanning electron microscopy and optical microscopy. The crystallographic structure and chemical composition of the film were determined by X-ray diffraction and energy dispersive spectroscopy, respectively. The results show that electroless Ni–P films were composed of the amorphous phase. The stable value P-content of the film was maintained at about 12 wt% with increasing bath temperature. The film surface was dense, and no cracking was found at 60 and 80 °C. However, the film deposited at 70 and 80 °C had a poor adherence to the substrate with evidence of delamination. The deposition rate of the film was increased with increasing plating temperature. At the same time, the deposition mechanism of the film on silicon substrate in the alkaline bath solution was addressed.