Thin film deposition of transparent materials by rear-side laser ablation: a novel configuration

A novel configuration for thin film deposition by rear-side laser ablation is presented. With transparent target materials it is possible to get both front and rear surface laser ablation. In the present work SiO2 thin films were deposited by rear laser ablation. In order to identify the species in each laser plume the generated plasmas (front and rear) were studied by Optical Emission Spectroscopy. Rear plasma has less ionized species as opposed to the front generated plasma. The deposited films were characterized by IR spectroscopy, ellipsometry and scanning electron microscopy. The results show better stoichiometry but lower evaporation rates for rear-side ablation than those deposited by front-side laser ablation. A simple interference model with a partially coherent source is used to account for the laser ablation process.