Excimer laser irradiation on NiP surface

Abstract

In this study, nickel-phosphorous (NiP) surface is irradiated by a KrF excimer laser beam. Atomic force microscope (AFM) and x-ray diffraction (XRD) are employed to study the surface morphology and the material structure. For laser fluence from 124 mJ/cm2 to 190 mJ/cm2, thin periodic structure morphology is formed in the irradiated region. When laser fluence exceeds 200 mJ/cm2, a microcosmic-smooth ripple morphology is obtained. The period of the second morphology is obviously larger than that of the first morphology. The morphology is dependent on the original surface condition, laser fluence and laser pulse number in the low laser fluence region and only laser fluence and laser pulse number in the high laser fluence region. One-dimensional thermal conduction model is used to predict the temperature rise in the irradiated region. Surface melting is predicted to take place at laser flunce about 200 mJ/cm2. The interaction mechanism between laser beam and NiP surface is proposed based on the theoretical calculation and experiment.