In situ infrared spectroscopy during La2O3 ALD using La( i PrCp)3 and H2O.

Infrared spectra of surface species have been obtained during atomic layer deposition using tris(isopropylcyclopentadienyl)lanthanum, La(iPrCp)3, and water as precursors at 160 °C and 350 °C. Gas-phase spectra of La(iPrCp)3are obtained for comparison. At low temperature, ligand exchange is seen to occur, and carbonate formation is found. With extended purging, the organic ligands are found to be stable on the surface, and carbonates are not formed. These observations indicate that carbonate formation is occurring during exposure to the precursors. At high temperature, the La precursor is observed to decompose leaving an opaque deposit containing relatively little hydrogen.