Thermodynamic Simulation of YBa₂Cu₃O_6+x Film Growth Using Aerosol MOCVD

Abstract
Future high power applications of high T_c superconducting materials (like YBa₂CU₃O_6+x demand thick films with excellent electrical properties. The use of thin film deposition techniques is only possible when high deposition rates can be reached. A novel aerosol MOCVD technique using a liquid source has recently been developed and is very promising for this purpose. The precursor materials used are the [MATH]-diketonates of yttrium, barium and copper, dissolved in diethylene glycol dimethyl ether ("diglyme") in various concentrations. A preliminary thermodynamic simulation of the process is a useful tool for a deeper understanding of the stability limits of the superconducting phase and the on-going reactions during deposition. The results of these simulations have been used to optimise the process conditions for YBa₂Cu₃O_6+x growth with good superconducting properties. A comparison between the simulation and the experimental results will be given and the influence of the main process parameters (deposition temperature, oxygen partial pressure, precursor concentration, ... ) will be shown.