CuBr laser treatment of titanium wafers

The use of lasers in materials processing is an increasingly attractive choice for high technology manufacturing. Factors influencing the laser ablation process include laser beam parameters, such as wavelength, energy or fluence and pulse length, the material properties of the target, such as melting temperature, thermal diffusion rate, optical reflectivity, and the ambient gas. We investigated the influence of laser treatment on titanium wafers with CuBr laser (lambda = 511nm) by scanning laser beam with distance between paths 20 mu m. The laser fluence varied from 4.7 J cm(-2) to 13.5 J cm(-2) and the laser beam scanning velocity from 25mm/s to 100mm/s with duration of 30 ns. The experiments were done in two kinds of ambient atmosphere: air and argon. The morphology of the irradiated surface was studied by scanning electron microscopy (SEM). SEM study showed that the laser irradiation caused a change in the surface morphology due to the processes of melting and subsequent resolidification as well as particle deposition from the vapor plume. The chemical state and composition of the irradiated titanium surface were determined using the Ti2p and O1s binding energy values and O/Ti intensity ratio. The XPS results indicated that on the irradiated titanium surface is formed oxide layer with stoichiometry close to TiO2. It was found that the ambient atmosphere is responsible for the change in the microstructure and chemical state of the titanium target.