Laser-induced etching

There are three categories of laser-assisted chemical reactions which have been employed to etch metals, semiconductors, and other inorganic materials. Lasers can be used to locally heat a solid to accelerate the rate of a thermally activated process. This is the most universally applicable method of laser-induced etching. Alternatively, the laser can be used to generate reactive gas-phase or liquid-phase species by photolytic decomposition of precursor molecules. Appropriate reactants have been identified for a wide variety of materials. Finally, the laser can be used to create photo-generated electrons and holes in semiconductors; these carriers then participate directly in the etching process. Highly selective etching can be achieved by capitalizing on the surface electronic properties which influence carrier generation or subsequent behavior. These three types of laser-induced reaction are reviewed.