Atomic Layer Deposition of SrS and BaS Thin Films Using Cyclopentadienyl Precursors

SrS and BaS thin films were grown on glass substrates using an atomic layer deposition (ALD) technique and (C₅ⁱPr₃H₂)₂Sr(THF) (1), (C₅Me₅)₂Sr(THF)_x (2), (C₅Me₅)₂Ba(THF)_x (3), and H₂S as precursors. Deposition temperatures were 120−460, 155−400, and 180−400 °C with 1, 2, and 3, respectively. Growth rate of the films varied between 0.6 and 3.0 Å/cycle and all the films were polycrystalline as deposited. The amount of C, H, and O residues was found to be 0.1−0.6 at. % in the films grown at 300 °C as determined by time-of-flight elastic recoil detection analysis (TOF-ERDA). Growth mechanisms for the films grown at different temperatures were also proposed. Crystal structures of 2 and 3 were determined.