Periodic structure formation during laser direct-writing of palladium acetate films: An optically regulated mechanism.

Laser direct-writing of micron-size metallic features from Pd acetate film precursors is achieved using a scanned cw Ar sup + laser. Marked periodic structure is observed in these features under a wide range of exposure conditions. A model based on laser reflectivity and transmittance measurements has been developed to describe the formation of the periodic structure. The model takes into account a complex relationship between optical absorption, laser-induced heating and reaction rate. The decomposition of Pd acetate to metal is endothermic and, therefore, this system differs fundamentally from the "explosive" crystallization of amorphous semiconductors.