In Situ Reaction Mechanism Studies on Atomic Layer Deposition of AlxSiyOz from Trimethylaluminium, Hexakis(ethylamino)disilane, and Water
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- 作者：Yoann Tomczak ; Kjell Knapas ; Suvi Haukka ; Marianna Kemell ; Mikko Heikkil盲 ; Marcel Ceccato ; Markku Leskel盲 ; Mikko Ritala
- 刊名：Chemistry of Materials
- 出版年：2012
- 出版时间：October 23, 2012
- 年：2012
- 卷：24
- 期：20
- 页码：3859-3867
- 全文大小：376K
- 年卷期：v.24,no.20(October 23, 2012)
- ISSN：1520-5002
文摘
Reaction mechanisms in the Al(CH3)3鈥揇2O鈥揝i2(NHEt)6鈥揇2O ALD process for AlxSiyOz were studied in situ with a quartz crystal microbalance (QCM) and a quadrupole mass spectrometer (QMS) at 200 掳C. Two other pulsing sequences were investigated too to assess the surface reactivity of Si2(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鈥揅H3 bonds was deduced from the results. Several pathways were considered for the adsorption of Si2(NHEt)6 on a hydroxylated surface. According to the results, the pathway where both Si atoms in the dimeric Si2(NHEt)6 precursor molecule bond to the surface with a cleavage of their Si鈥揝i 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 Si2(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.