In-Situ Gas-Phase FTIR Monitoring of MOCVD Processes: LaF3 Films Using the Second Generation La(hfac)3·diglyme Precursor

Abstract

In-situ gas-phase Fourier transform infrared spectroscopy (FTIR) studies of thermally activated processes occurring in the metal–organic chemical vapor deposition (MOCVD) of La(hfac)3·diglyme provide evidence that the precursor can be evaporated from the melt up to 130 °C without side decomposition processes. In contrast, under typical operating conditions in hot-wall MOCVD processes, the precursor undergoes different demolition pathways. Under Ar, it is stable up to 300 °C. At higher temperatures, decomposition involves the β-diketonate array leaving the glyme coordination intact. Materials thus deposited have greater carbon contamination. Introducing O2 into the stream promotes diglyme dissociation and prevents carbon contamination in the film. Thermally activated processes show close analogies with those of the free Hhfac ligand. Fluorinated ketones and acylketenes are formed as the main decomposition products. Complementary insights into the factors responsible for the contamination associated with the deposition processes have been obtained by X-ray photoelectron spectroscopy (XPS) studies.