Image processing plume fluence for superconducting 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). PLD produces a plume of highly energetic components which is directed onto a suitable substrate for growing required films. Image processed plume emissions from a YBa2Cu3O7-x target are in situ monitored at 553.5 nm to determine two-dimensional spatial information about the plume. Simultaneously, time-of-flight (TOF) information also at 553.5 nm is gathered from two positions along the plume path. Manual and fuzzy-logic based regulation of laser beam energy based on this TOF feedback has resulted in improved film quality and reproducibility. Imaging of the plume under various deposition conditions, both with and without process control, will help to improve the understanding of changing environmental conditions on the plume characteristics growth and quality.