Grading PrxCa1-xMnO3 thin films by metalorganic chemical vapor deposition

摘要

The present invention discloses a method to achieve grading PCMO thin film for use in RRAM memory devices since the contents of Ca, Mn and Pr in a PCMO film can have great influence on its switching property. By choosing precursors for Pr, Ca and Mn having different deposition rate behaviors with respect to deposition temperature or vaporizer temperature, PCMO thin film of grading Pr, Ca or Mn distribution can be achieved by varying that process condition during deposition. The present invention can also be broadly applied to the fabrication of any multicomponent grading thin film process by varying any of the deposition parameters after preparing multiple precursors to have different deposition rate behaviors with respect to that particular process parameter. The present invention starts with a proper selection of precursors in which the selected precursors have different deposition rates with respect to at least one deposition condition such as deposition temperature or vaporizer temperature. The precursors can then be arranged in different delivery systems, or can be pre-mixed in a proper ratio for use in a delivery system, or in any other combinations such as a mixture of two or three liquid precursors using a direct liquid injection and a separate gaseous precursor delivery system for gaseous process gas. Then by varying the appropriate deposition condition, a grading thin film can be achieved.