Rate and composition control by atomic absorption spectroscopy for the coevaporation of high Tc superconducting films

Atomic absorption spectroscopy has been used to control the deposition rates during coevaporation processes with multiple electron‐beam sources. This technique is material specific and thus allows the deposition rate of each component to be controlled independently. Because only a light beam is needed to interact with the vapor stream, the sampling region can be selected to be very close to the substrate for precise control of the film composition. With its high sensitivity and no limitations on operation pressure, this technique offers some unique advantages for the preparation of high Tc superconducting films by coevaporation in a high oxygen partial pressure environment. The performance of a multi‐source deposition controller and the resultant film properties are presented.