Energy Parameters of the Simplest Chemical Reactions Occurring at the First Stages of Silicon Electrochemical Etching – DFT-Modeling

Authors F. Ptashchenko

National University “Odessa Maritime Academy”, 8, Didrikhson st., 65029 Odesa, Ukraine

Issue Volume 15, Year 2023, Number 5
Dates Received 10 August 2023; revised manuscript received 17 October 2023; published online 30 October 2023
Citation F. Ptashchenko, J. Nano- Electron. Phys. 15 No 5, 05003 (2023)
PACS Number(s) 82.45. – h, 82.65. + r
Keywords Porous silicon (3) , Electrochemical etching, DFT-calculations.

Based on quantum chemical calculations, the reactions of removal of surface hydrogen atoms, which occur at the first stages of silicon etching in HF solutions under the action of various fluoride ionic complexes, are studied. To do this, a method has been developed for reliable estimation of the energy parameters of chemical reactions with a changing charge state of a cluster that occur on the surface of bulk silicon based on the results of calculations performed on clusters of finite sizes. It is shown that in aqueous HF solutions the reactions of removal of surface hydrogen atoms can occur both with current flowing through the silicon/electrolyte system and without it. The reactions of removing the hydrogen coating of the silicon surface occur only under the influence of "light" ionic fluoride complexes containing no more than one HF molecule. Based on simulations, the reasons for the slowdown in purely chemical etching of silicon in high concentration HF are explained

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