Thin film deposition of lanthanum manganite perovskite by the ALE process

Abstract

Deposition of thin films of LaMnO ₃ from β-diketonate-type (thd) precursors and ozone in an ALE reactor has been demonstrated. At low temperatures, the Mn-O growth from the Mn(thd) ₃ precursor is retarded by the growth of the La-O deposit. By tuning of the pulsing ratio, full control of the stoichiometry of the deposited film is achieved in the temperature interval 300-400 °C. In this temperature range, the composition set by the pulsing ratio is transferred, within a few percent accuracy, to the deposited thin film. Indications for an ‘ALE window’ are found around 250-300 °C. Amorphous LaMnO ₃ films could be deposited at temperatures as low as 250 °C, however, the deposition of crystalline films requires temperatures above 350 °C. X-Ray diffraction analyses show that the crystalline LaMnO ₃ film was of the rhombohedral type with a=5.46(2) Å and α=60.28(10)°.