Influence of wavelength and pulse duration on the selective laser ablation of WOx, VOx and MoOx thin films

Abstract

In this paper, we present a study of the laser scribing of WO x , VO x , and MoO x films, deposited onto crystalline silicon, with three different wavelengths (355 nm, 532 nm, and 1064 nm) and in two temporal regimes in pulse width, picosecond and nanosecond. For each case, we measure the fluence threshold to remove the transition metal oxides (TMO) film and the fluence threshold to induce damage in the crystalline silicon substrate. The relation between the process parameters and the morphological changes produced in the oxide films is also analysed. The selection of the proper laser source allows a wide parametric window, leading to the complete removal of the TMO films without alteration of the crystalline silicon substrate. Morphological changes of the ablated regions were characterized through confocal microscopy and the relationships between the dimensions of the craters and the ablation parameters were analyzed.Finally, we present results on the isolation of diodes and their electrical characteristics, showing the quality of the laser scribing processes.