Reaction Mechanism of Atomic Layer Deposition of Al on the Si (100) Surface: A Density Functional Theory Study

Abstract:

Using H₂ and Al (CH₃)₃(TMA) as precursor, we investigated the atomic layer deposition mechanism of the metal Al on Si (100) surface by density functional theory. The reaction process comprises two half-reaction depositions: TMA "half-reaction" includes I and II on the H blunt reaction surface; H₂ "half-reaction" includes the subsequent reaction Ⅲ and Ⅳ. In the TMA half reaction process, trimethyl aluminum first molecularly adsorbed in the active site of H*-Si₉H₁₂-H* to form a stable complex in the form of chemical adsorption state. Potential curves show that at 298 K, adsorption energy is -2.26kJ/mol, with respect to the chemical adsorption state, the activation barrier energy is 124.72kJ/mol, and finally the whole exothermic reaction energy is 41.4kJ/mol. After H₂ half reaction, the bond length between Al-Si can be considered equal; two Al-C bonds become relatively stable molecular structure. The adsorption energy is -0.10kJ/mol at 298 K, and the activation barrier energy 189.15kJ/mol. The results show that two half-reaction process mechanism is similar, TMA endothermic reaction needs more energy to be carried out under heating conditions ; endothermic and exothermic reaction energy is basic balance, the activation energy is large, so the reaction is the best using ionized gas to be carried out.

• Periodical: Advanced Materials Research (Volumes 941-944)
• Pages: 1283-1287
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.941-944.1283
• Online since: June 2014
• Authors: Mao Jin Dong*, Ran Fang, Yu Qing Xiong, Duo Shu Wang, Ji Zhou Wang, Chen Li, Ling Zhang
• Keywords: Aluminum (Al), Atomic Layer Deposition (ALD), Density Functional Theory (DFT), Reaction Mechanism

References

[1] L. Jeloaica, A. Esteve, M. Djafari Rouhani et al: Applied Physics Letters, Vol. 83 (2003), p.542.

[2] Eunsuk Choi Seung-Chul Ha, Soo-Hyun Kim and Jae Sung Roh: Thin Solid Films, Vol. 476(2005), p.252.

[3] Mathew D. Halls and Krishnan Raghavachari: J. Phys. Chem. B, Vol. 108(2004), p.4058.

[4] Jie Ren, Ya-Tong Zhang and David Wei Zhang: Journal of Molecular Structure: THEOCHEM, Vol. 803 (2007), p.23–28.

[5] Xiong Yu-Qing, Li Xing-Cun, Chen Qiang, et al: Chin. Phys. B, Vol. 21(2012), p.078105.

[6] Chen Wei. Atomic layer deposition reaction mechanism of the gate dielectric layer of high dielectric constant of quantum chemical studies (Master's thesis). 2005. Fudan University (In Chinese).

[7] Chen Jingbo. Quantum chemical calculations of several chemical reaction mechanism (Thesis) . 2009 Central South University (In Chinese).