Al2O3 Atomic Layer Deposition with Trimethylaluminum and Ozone Studied by in Situ Transmission FTIR Spectroscopy and Quadrupole Mass Spectrometry

Abstract

The atomic layer deposition (ALD) of Al2O3 using sequential exposures of Al(CH3)3 and O3 was studied by in situ transmission Fourier transform infrared (FTIR) spectroscopy and quadrupole mass spectrometry (QMS). The FTIR spectroscopy investigations of the surface reactions occurring during Al2O3 ALD were performed on ZrO2 particles for temperatures from 363 to 650 K. The FTIR spectra after Al(CH3)3 and ozone exposures showed that the ozone exposure removes surface AlCH3* species. The AlCH3* species were converted to AlOCH3* (methoxy), Al(OCHO)* (formate), Al(OCOOH)* (carbonate), and AlOH* (hydroxyl) species. The TMA exposure then removes these species and reestablishes the AlCH3* species. Repeating the TMA and O3 exposures in a sequential reaction sequence progressively deposited the Al2O3 ALD film as monitored by the increase in absorbance for bulk Al2O3 infrared features. The identification of formate species was confirmed by separate formaldehyde adsorption experiments. The formate species were tempera...