ABSTRACT
Laser-ablated material for stoichiometric thin-film deposition enables the manufacture of engineered crystalline products ranging from superconductors to solid lubricants. The complexity accommodation of product and process modeling, control technology selection, and data error analysis methods are effective concurrent engineering linkages for laser-deposited material processing. Fuzzy logic offers in situ feedback control of poorly modeled and noisy data process conditions, often encountered in process automation systems, beyond that possible with traditional proportional-integral-derivative controllers. Fuzzy control benefits from the encoding of expert operator knowledge for maximizing plume output even with nonlinear and only partially measurable process parameters. The high kinetic energy involved in laser-ablated material, with wide-ranging target compounding options plus additional chemical sources such as magnetron sputtering combine to enable versatile stoichiometric material growth capabilities. Laser-deposited material process sensing of substrate thickness and thickness rate permits online deposited film microstructure acquisition, using a quartz crystal microbalance positioned in the direct plume plasma without shadowing the substrate.
