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[摘要]：Reaction mechanisms in the Al(CH3)(3)-D2O-Si-2(NHEt)(6)-D2O ALD process for AlxSiyOz, were studied in situ with a quartz crystal microbalance (QCM) and a quadrupole mass spectrometer (QMS) at 200 degrees C. Two other pulsing sequences were investigated too to assess the surface reactivity of Si-2(NHEt)(6) and Al(CH3)(3). The resulting films were extensively analyzed with X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy. The main byproducts observed with QMS were CDH3 and NDHC2H5. The incorporation of methyl groups from TMA into the film through the formation of Si-CH3 bonds was deduced from the results. Several pathways were considered for the adsorption of Si-2(NHEt)(6) on a hydroxylated surface. According to the results, the pathway where both Si atoms in the dimeric Si-2(NHEt)(6) precursor molecule bond to the surface with a cleavage of their Si Si bond is preferred. A model based on the QCM and XPS data was build to better characterize the mechanism. The calculations indicated that 1.3 methyl ligands of Al(CH3)(3) and 3.8 NHEt ligands of Si-2(NHEt)(6) are released in average during their respective metal precursor pulses in reactions with surface hydroxyl groups, the rest being eliminated during the following D2O pulses. |
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