Suppression of dewetting phenomena during excimer laser melting of thin metal films on SiO2

Pulsed excimer laser irradiation has been used to fully melt 200 nm films of elemental Au and Ni on SiO2 substrates. With the use of a capping layer of SiO2 and line irradiation via projection optics, the typical liquid-phase dewetting processes associated with these metals on SiO2 has been suppressed. In a series of experiments varying line widths and fluence, a process region is revealed immediately above the complete melting threshold for which the films remain continuous and smooth after melting and resolidification. Simple energetic arguments for mechanisms leading to initiation of dewetting support these observations, and a gas-mediated model is proposed to describe the process conditions that are necessary for the suppression of dewetting.