INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM

The influence of silicon wafer crystallographic orientation on the formation of porous silicon during anodization in an HF solution is studied. Cross-section SEM image comparison of samples with different crystallographic orientations has shown that (111) Si samples exhibit a more branching, tree-li...

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Main Authors: N. L. Grevtsov, A. V. Klimenka, A. D. Hurbo, V. P. Bondarenko
Format: Article
Language:Russian
Published: Educational institution «Belarusian State University of Informatics and Radioelectronics» 2020-03-01
Series:Doklady Belorusskogo gosudarstvennogo universiteta informatiki i radioèlektroniki
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Online Access:https://doklady.bsuir.by/jour/article/view/2593
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author N. L. Grevtsov
A. V. Klimenka
A. D. Hurbo
V. P. Bondarenko
author_facet N. L. Grevtsov
A. V. Klimenka
A. D. Hurbo
V. P. Bondarenko
author_sort N. L. Grevtsov
collection DOAJ
description The influence of silicon wafer crystallographic orientation on the formation of porous silicon during anodization in an HF solution is studied. Cross-section SEM image comparison of samples with different crystallographic orientations has shown that (111) Si samples exhibit a more branching, tree-like pore structure with a higher porosity value compared to (100) Si samples. This phenomenon is explained by pointing out differences in crystal structure and numbers of Si-Si chemical bonds in different crystallographic directions. Namely, in (100)-oriented silicon crystals every surface Si atom has two bonds connecting it to atoms underneath it, as well as two broken bonds able to interact with Fions. Through electron injection into silicon, enough energy is applied to break the underlying bonds, forming SiF as a result. The presence of two Fions bonded with every surface silicon atom leads to weakening the bonds of surface silicon atoms with the underlying atoms, thus making the process of breaking the Si-Si bonds more energy efficient. As for (111)-oriented crystals, silicon atoms only have one broken surface bond, and breaking backbonds with underlying silicon atoms requires a higher value of activation energy due to their larger amount (three as opposed to two for (100) silicon). It is concluded that this very reason leads to slower etching speeds of (111)-oriented silicon wafers. The results help evaluate the way the silicon crystal structure affects the etching process, including its speed and direction, which is an especially important factor to consider when forming (111)-oriented porous silicon.
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institution Kabale University
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publishDate 2020-03-01
publisher Educational institution «Belarusian State University of Informatics and Radioelectronics»
record_format Article
series Doklady Belorusskogo gosudarstvennogo universiteta informatiki i radioèlektroniki
spelling doaj-art-36f1caca2f9b4d0684640fbc9309b7a22025-08-20T03:44:58ZrusEducational institution «Belarusian State University of Informatics and Radioelectronics»Doklady Belorusskogo gosudarstvennogo universiteta informatiki i radioèlektroniki1729-76482020-03-01181596610.35596/1729-7648-2020-18-1-59-661564INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISMN. L. Grevtsov0A. V. Klimenka1A. D. Hurbo2V. P. Bondarenko3Belarusian State University of Informatics and RadioelectronicsBelarusian State University of Informatics and RadioelectronicsBelarusian State University of Informatics and RadioelectronicsBelarusian State University of Informatics and RadioelectronicsThe influence of silicon wafer crystallographic orientation on the formation of porous silicon during anodization in an HF solution is studied. Cross-section SEM image comparison of samples with different crystallographic orientations has shown that (111) Si samples exhibit a more branching, tree-like pore structure with a higher porosity value compared to (100) Si samples. This phenomenon is explained by pointing out differences in crystal structure and numbers of Si-Si chemical bonds in different crystallographic directions. Namely, in (100)-oriented silicon crystals every surface Si atom has two bonds connecting it to atoms underneath it, as well as two broken bonds able to interact with Fions. Through electron injection into silicon, enough energy is applied to break the underlying bonds, forming SiF as a result. The presence of two Fions bonded with every surface silicon atom leads to weakening the bonds of surface silicon atoms with the underlying atoms, thus making the process of breaking the Si-Si bonds more energy efficient. As for (111)-oriented crystals, silicon atoms only have one broken surface bond, and breaking backbonds with underlying silicon atoms requires a higher value of activation energy due to their larger amount (three as opposed to two for (100) silicon). It is concluded that this very reason leads to slower etching speeds of (111)-oriented silicon wafers. The results help evaluate the way the silicon crystal structure affects the etching process, including its speed and direction, which is an especially important factor to consider when forming (111)-oriented porous silicon.https://doklady.bsuir.by/jour/article/view/2593silicon nanostructuresporous siliconelectrochemical etching
spellingShingle N. L. Grevtsov
A. V. Klimenka
A. D. Hurbo
V. P. Bondarenko
INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
Doklady Belorusskogo gosudarstvennogo universiteta informatiki i radioèlektroniki
silicon nanostructures
porous silicon
electrochemical etching
title INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
title_full INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
title_fullStr INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
title_full_unstemmed INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
title_short INFLUENCE OF SILICON WAFER CRYSTALLOGRAPHIC ORIENTATION ON ANODIZATION MECHANISM
title_sort influence of silicon wafer crystallographic orientation on anodization mechanism
topic silicon nanostructures
porous silicon
electrochemical etching
url https://doklady.bsuir.by/jour/article/view/2593
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