Controlling the Wet-Etch Directionality in Nanostructured Silicon

Aabdin, Zainul; Ghosh, Tanmay; Pacco, Antoine; Raj, S. Shanmuga Sundara; Bich, Hue Thi; Saidov, Khakimjon; Weei, Tjiu Weng; Anand, Utkarsh; Holsteyns, Frank; Bosman, Michel; Mirsaidov, Utkur

doi:10.1021/acsaelm.2c00824

Cited by 10 publications

(10 citation statements)

References 52 publications

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“…To better understand how the NW surface evolves during the etching, we tracked the entire process in real-time with LP-TEM (Figure 3). [25,[28][29][30] The plot of the width of Mo NWs (Figure 3B) extracted from the in situ TEM images series (Figure 3C; Video S1, Supporting Information) shows the gradual width recess for four metal NWs, where the etching rate, defined as the rate of the NW width reduction, remained almost constant at ≈0.02 nm s −1 throughout the etching. However, a closer examination of the selected area in Figure 3D reveals that some pits formed at the GBs at the early stage (Figure 3D: t -t 0 = 0-130 s), suggesting that GBs are more susceptible to etching than the sidewalls.…”

Section: Resultsmentioning

confidence: 99%

“…The details of the fabrication steps of the chips and liquid cells are described in our earlier studies. [25,[28][29][30] Materials: The etching solutions used in this study were prepared from the following chemicals: hydrogen peroxide (30% H 2 O 2 , Dickson Chemical, Singapore), hydrofluoric acid (48% HF, Cat. No.…”

Section: Methodsmentioning

confidence: 99%

“…For in situ studies, liquid cells were first assembled using the TEM chips in a custom-built liquid-flow TEM holder. [25,[28][29][30] After inserting the holder into the TEM, the H 2 O 2 aqueous solution (1% (v/v)) was introduced into the holder with a syringe pump at a flow rate of 5−10 μL min −1 . The in situ image series shown in Figure 3 were recorded at a rate of 10 frames per second with an electron flux of < 20 e − Å −2 s −1 .…”

Section: Methodsmentioning

confidence: 99%

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Controlled Stepwise Wet Etching of Polycrystalline Mo Nanowires

Saidov,

Erofeev,

Aabdin

et al. 2023

Adv Funct Materials

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With the persistent downscaling of integrated circuits, molybdenum (Mo) is currently considered a potential replacement for copper (Cu) as a material for metal interconnects. However, fabricating metal nanostructures with critical dimensions of the order of 10 nm and below is challenging. This is because the very high density of grain boundaries (GBs) results in highly non‐uniform surface profiles during direct wet etching. Moreover, wet etching of Mo with conventional aqueous solutions is problematic, as products of Mo oxidation have different solubility in water, which leads to increased surface roughness. Here, a process is shown for achieving a stable and uniform soluble surface layer of Mo oxide by wet oxidation with H2O2 dissolved in IPA at −20 °C. The oxide layer is then selectively dissolved, and by repeating the oxidation and dissolution multiple times, a uniform etch profile is demonstrated with a fine control over the metal recess. Ultimately, this presents a method of precise and uniform wet etching for Mo and other metals needed to fabricate complex nanostructures that are critical in developing next‐generation electronic devices.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Controlled Stepwise Wet Etching of Polycrystalline Mo Nanowires

Saidov,

Erofeev,

Aabdin

et al. 2023

Adv Funct Materials

Self Cite

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“…In contrast, precipitation phenomena observed in aqueous solutions and analyses of growth kinetics suggest an elevated concentration of c (OH – ) under irradiation. Likewise, LP-TEM studies on c (OH – )-driven Si etching are reported. , This is unexpected at low pH.…”

mentioning

confidence: 76%

“…Likewise, LP-TEM studies on c(OH − )-driven Si etching are reported. 19,20 This is unexpected at low pH.…”

mentioning

confidence: 91%

Tailoring the Acidity of Liquid Media with Ionizing Radiation: Rethinking the Acid–Base Correlation beyond pH

Fritsch

Körner

Couasnon

et al. 2023

J. Phys. Chem. Lett.

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Advanced in situ techniques based on electrons and X-rays are increasingly used to gain insights into fundamental processes in liquids. However, probing liquid samples with ionizing radiation changes the solution chemistry under observation. In this work, we show that a radiation-induced decrease in pH does not necessarily correlate to an increase in acidity of aqueous solutions. Thus, pH does not capture the acidity under irradiation. Using kinetic modeling of radiation chemistry, we introduce alternative measures of acidity (radiolytic acidity π* and radiolytic ion product K W*), that account for radiation-induced alterations of both H+ and OH– concentration. Moreover, we demonstrate that adding pH-neutral solutes such as LiCl, LiBr, or LiNO3 can trigger a significant change in π*. This provides a huge parameter space to tailor the acidity for in situ experiments involving ionizing radiation, as present in synchrotron facilities or during liquid-phase electron microscopy.

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Dielectric‐Based Metamaterials for Near‐Perfect Light Absorption

Wang,

Qin,

Duan

et al. 2024

Adv Funct Materials

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The emergence of metamaterials and their continued prosperity have built a powerful working platform for accurately manipulating the behavior of electromagnetic waves, providing sufficient possibility for the realization of metamaterial absorbers with outstanding performance. However, metamaterial absorbers composed of metallic materials typically possess many unfavorable factors, such as non‐adjustable absorption, easy oxidation, low‐melting, and expensive preparation costs. The selection of dielectric materials provides excellent alternatives due to their remarkable properties, thus dielectric‐based metamaterial absorbers (DBMAs) have attracted much attention. To promote breakthroughs in DBMAs and guide their future development, this work systematically and deeply reviews the recent research progress of DBMAs from four different but progressive aspects, including physical principles; classifications, material selections and tunable properties; preparation technologies; and functional applications. Five different types of theories and related physical mechanisms, such as Mie resonance, guided‐mode resonance, and Anapole resonance, are briefly outlined to explain DBMAs having near‐perfect absorption performance. Mainstream material selections, structure designs, and different types of tunable DBMAs are highlighted. Several widely utilized preparation methods for customizing DBMAs are given. Various practical applications of DBMAs in sensing, stealth technology, solar energy absorption, and electromagnetic interference suppression are reviewed. Finally, some key challenges and feasible solutions for DBMAs’ future development are provided.

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Controlling the Wet-Etch Directionality in Nanostructured Silicon

Cited by 10 publications

References 52 publications

Controlled Stepwise Wet Etching of Polycrystalline Mo Nanowires

Controlled Stepwise Wet Etching of Polycrystalline Mo Nanowires

Tailoring the Acidity of Liquid Media with Ionizing Radiation: Rethinking the Acid–Base Correlation beyond pH

Dielectric‐Based Metamaterials for Near‐Perfect Light Absorption

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