Laser-induced local CVD and simultaneous etching of tungsten

Tungsten dots are grown by laser-assisted chemical vapour deposition from a gas mixture of tungsten hexafluoride and hydrogen on a supported thin tungsten film. Local growth is achieved by confined heating of the substrate using the focused beam of a cw Ar+ laser. By in situ monitoring the lateral growth of the dots with the help of a microscope-video system, real-time data of the lateral growth have been recorded from single experiments in order to study the kinetics of the process. The competing kinetics of different reaction paths, controlled by the ratio of the precursor gases, investigated. It leads to a change of the apparent activation energy and the morphology.