Process control and pulsed laser deposition of materials

Pulsed-laser deposition (PLD) is a very powerful and rapid deposition techn ique, which can produce exceptional-quality thin films. Although PLD has tr emendous versatility and potential, PLD capabilities are still constrained by a lack of process control. At the Air Force Research Laboratory on-site at Wright-Patterson AFB, we are developing in-situ/real-time control method ologies for PLD and other thin-film deposition processes. We have identifie d appropriate sensors for closed-loop feedback control and utilized them wi th YBa2Cu3O7-x, (YBCO) to identify critical process control parameters. Con trol instrumentation has recently been improved by the addition of moveable fixed-position plume-emission sensors. The reproducibility of YBCO film qu ality increased significantly when process control was applied to PLD proce ssing. PLD process control techniques were applied during simulated and actual BST O depositions. A comparison of deposition control with the controlling sens or at different distances from the substrate heater position is discussed. Further process refinement using Lime-resolved spectral components of the P LD plume on subsequent film quality is also discussed.