Atomistic insights into bias-induced oxidation on passivated silicon surface through ReaxFF MD simulation

J Gao and XC Luo and WK Xie and Y Qin and RMM Hasan and PF Fan, APPLIED SURFACE SCIENCE, 626, 157253 (2023).

DOI: 10.1016/j.apsusc.2023.157253

The study investigated the bias-induced oxidation through ReaxFF molecular dynamics simulations in order to bridge the knowledge gaps in the understanding of physical-chemical reaction at the atomic scale. Such an understanding is critical to realise accurate process control of bias-induced local anodic oxidation nano lithography. In this work, we simulated bias-induced oxidation by applying electric fields to passivated silicon surfaces and performed a detailed analysis of the simulation results to identify the primary chemical components involved in the reaction and their respective roles. In contrast to surface passivation, bias-induced oxidation led mainly to the creation of Si-O- Si bonds in the oxide film, along with the consumption of H2O and the generation of H3O+ in the water layer, whereas the chemical composition on the oxidised surface remained essentially unchanged with a mixture of Si-O-H, Si-H, Si-H2, H2O-Si and Si-O-Si bonds. Furthermore, parametric studies indicated that increased electric field strength and humidity did not significantly alter the surface chemical composition but notably enhanced the bias-induced oxidation, as indicated by the increased number of Si-O-Si bonds and oxide thickness in simulation results. A good agreement is achieved between the simulation and experimental results.

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