In Situ Studies of the Nucleation Mechanisms of Tris(Cyclopentadienyl)Cerium As Cerium Dopant Source in Srs : Ce Thin Films for Electroluminescent Displays

A systematic evaluation was made of the performance and efficiency of tris(cyclopentadienyl)cerium, Ce(CPD), as potential dopant source in atomic layer epitaxy (ALE) and chemical vapor deposition (CVD) of Ce-doped strontium sulfide (SrS:Ce) for thin-film electroluminescent display applications. In situ growth and characterization studies were carried out, without a vacuum break, of the adsorption and associated dissociation mechanisms of Ce(CPD) within the substrate temperature window typically employed in ALE and CVD SrS:Ce. Associated findings were compared to results from tetrakis(2,2,6,6-tetramethyl-3,5-heptadionato)cerium, cerium, Ce(tmhd)(4), which was used as a comparative performance baseline. In this respect, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry studies indicated that, within the typical thermal budget used in ALE and CVD of SrS:Ce films, the Ce(CPD) source decomposed more efficiently than its Ce(tmhd)(4) counterpart, as supported by the observation of reduced hydrocarbon-based surface contamination and a cleaner Ce phase. It was concluded that Ce(CPD) might be a better candidate than Ce(tmhd)(4) for applications as Ce dopant source in ALE and CVD SrS:Ce films. (C) 2001 The Electrochemical Society.