Image processing plume fluence for process control of pulsed-laser thin-film depositions

Process control is a crucial element in all deposition techniques. It is especially elusive in the versatile and efficient deposition technique known as pulsed-laser-deposition (PLD). Image processed emissions as well as signal processed intensity measurements from the plume of a YBa2Cu3O7-x (YBCO) target are monitored in situ to determine two dimensional spatial and time-of-flight (TOF) information about plume components. Manual and fuzzy-logic based regulation of laser energy and pressure, simultaneously, based on TOF feedback have resulted in improved film quality and repeatability of the PLD thin-film depositions. The plume was imaged under various deposition conditions, including in situ changing of beam focus relative to the target surface, chamber pressure, and laser beam energy. Analysis of the collected images will provide an increased understanding of the effect of changing environmental conditions in order to improve the deposited thin film quality.