A Study on Electrochemical Machining Method in Ultrapure Water. Etching Process of Hydrogen-Terminated Si(001) Surface Atom by Hydroxyl Function

Autor:	Yasushi Toma, Kikuzi Hirose, Hidekazu Goto, Yuzo Mori, Itsuki Kobata
Rok vydání:	2001
Předmět:	Pseudopotential Materials science Local density of states Hydrogen chemistry Silicon Mechanical Engineering Ultrapure water chemistry.chemical_element Molecule Ionic bonding Physical chemistry Basis set
Zdroj:	Journal of the Japan Society for Precision Engineering. 67:1169-1174
ISSN:	1882-675X 0912-0289
DOI:	10.2493/jjspe.67.1169
Popis:	In order to reveal the mechanism of the electrochemical etching process in ultrapure water, first-principles molecular-dynamics simulations for the etching process of hydrogen-terminated Si(001) surfaces interacting with OH molecules were carried out on the basis of the Kohn-Sham local-density-functional formalism. A plane-wave basis set was used, and the cut-off energy is 327eV(24Ry). A norm-conserving pseudopotential was also used. The standard molecular-dynamics method for the optimization of the ionic system and the preconditioned conjugate-gradient (CG) method for the quenching procedure of the electronic degrees of freedom were adopted. The optimized ionic configurations, local density of states, and atomic and bond populations for OH chemisorbed Si(001) surfaces were determined and the electronic structures relevant to the etching mechanism were clarified. It was confirmed that the interaction between two OH molecules and the hydrogen-terminated surface silicon atom on the step edge breaks the Si-Si back-bond and initiates the etching process forming a SiH2(OH)2 molecule.
Databáze:	OpenAIRE
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