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The dual role of silver during silicon etching in HF solution.

Abouda-Lachiheb M, Nafie N, Bouaicha M - Nanoscale Res Lett (2012)

Bottom Line: In this paper, we give experimental results arguing the dual role that silver has during the formation of silicon nanostructures.Through our investigations, we tracked the silver particles that indicated which mechanism is involved.Characterizations of the prepared samples were made using a scanning electron microscope.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l'Energie, Technopole de Borj-Cedria, BP 95, Hammam-Lif, Tunis, 2050, Tunisia. Mongi.Bouaicha@crten.rnrt.tn.

ABSTRACT
It was reported that during silicon etching, silver was subjected to have a controversial role. Some researchers debate that silver protects silicon, and, at the same time, other ones confirm that silver catalyzes silicon underneath. In this paper, we give experimental results arguing the dual role that silver has during the formation of silicon nanostructures. We give a proof that the role of silver depends on the experimental details and the intrinsic properties of silver during its deposition on the silicon wafer. Through our investigations, we tracked the silver particles that indicated which mechanism is involved. Characterizations of the prepared samples were made using a scanning electron microscope.

No MeSH data available.


Schematic illustration of the etching mechanism. (A) the one-step process and (B) the two-step process.
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Figure 4: Schematic illustration of the etching mechanism. (A) the one-step process and (B) the two-step process.

Mentions: The aptitude of oxidizing silicon depends on the silicon status; from values in Table 1, we can deduce that oxidizing pure silicon substrate (intrinsic silicon) is easier than oxidizing pure boron material. We can extrapolate that boron-doped silicon has an effective electronegativity value ranging between 1.90 (Pure Si) and 2.04 (Pure B). Consequently, in the case of sample A where silver ions are deposited on the Si substrate, there is transfer of electrons from Si to silver. Therefore, the region underneath silver becomes poor in electrons as compared to the region around silver nanoparticles. Hence, oxidizing Si around silver particles (P-doped Si) becomes more important than the Si underneath it, which behaves like P++-doped Si. Thus, the etching of oxidized sites around silver particles starts leading to the formation of SiNWs (Figure 4A, processes a-c). However, in the case of sample B, due to the neutral region formed underneath the evaporated silver nanoparticles, Si around them (P-doped Si) is a difficult oxidized region as compared to Si underneath them that behaves like intrinsic Si. As a result, etching starts underneath Ag particles leading to pores formation (Figure 4B, processes a-c).


The dual role of silver during silicon etching in HF solution.

Abouda-Lachiheb M, Nafie N, Bouaicha M - Nanoscale Res Lett (2012)

Schematic illustration of the etching mechanism. (A) the one-step process and (B) the two-step process.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472321&req=5

Figure 4: Schematic illustration of the etching mechanism. (A) the one-step process and (B) the two-step process.
Mentions: The aptitude of oxidizing silicon depends on the silicon status; from values in Table 1, we can deduce that oxidizing pure silicon substrate (intrinsic silicon) is easier than oxidizing pure boron material. We can extrapolate that boron-doped silicon has an effective electronegativity value ranging between 1.90 (Pure Si) and 2.04 (Pure B). Consequently, in the case of sample A where silver ions are deposited on the Si substrate, there is transfer of electrons from Si to silver. Therefore, the region underneath silver becomes poor in electrons as compared to the region around silver nanoparticles. Hence, oxidizing Si around silver particles (P-doped Si) becomes more important than the Si underneath it, which behaves like P++-doped Si. Thus, the etching of oxidized sites around silver particles starts leading to the formation of SiNWs (Figure 4A, processes a-c). However, in the case of sample B, due to the neutral region formed underneath the evaporated silver nanoparticles, Si around them (P-doped Si) is a difficult oxidized region as compared to Si underneath them that behaves like intrinsic Si. As a result, etching starts underneath Ag particles leading to pores formation (Figure 4B, processes a-c).

Bottom Line: In this paper, we give experimental results arguing the dual role that silver has during the formation of silicon nanostructures.Through our investigations, we tracked the silver particles that indicated which mechanism is involved.Characterizations of the prepared samples were made using a scanning electron microscope.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l'Energie, Technopole de Borj-Cedria, BP 95, Hammam-Lif, Tunis, 2050, Tunisia. Mongi.Bouaicha@crten.rnrt.tn.

ABSTRACT
It was reported that during silicon etching, silver was subjected to have a controversial role. Some researchers debate that silver protects silicon, and, at the same time, other ones confirm that silver catalyzes silicon underneath. In this paper, we give experimental results arguing the dual role that silver has during the formation of silicon nanostructures. We give a proof that the role of silver depends on the experimental details and the intrinsic properties of silver during its deposition on the silicon wafer. Through our investigations, we tracked the silver particles that indicated which mechanism is involved. Characterizations of the prepared samples were made using a scanning electron microscope.

No MeSH data available.