Macropore growth in a prepatterned p‐type silicon wafer

Kobayashi, Kei; Harraz, Farid A.; Izuo, Shinichi; Sakka, Tetsuo; Ogata, Yukio H.

doi:10.1002/pssa.200674325

Cited by 21 publications

(11 citation statements)

References 15 publications

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“…The thickness of a nanorod remains constant and a pore is grown only in the depth direction. 13) Figure 6 shows the SEM images of the nanorod array with an approximately 350 nm diameter formed in p-type silicon when two-step currents (40 mA, 200 s + 38 mA, 1600 s) are applied in order to further reduce significantly the diameter of a nanorod using the same etch-pit mask pattern shown in Fig. 1(c).…”

Section: Resultsmentioning

confidence: 99%

Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon

Kim

Lyu

et al. 2010

Jpn. J. Appl. Phys.

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We carried out a study on the change in pore wall thickness depending on the current density in p-type silicon. We attempted the formation of a uniform macropore or nanorod array with a high aspect ratio in p-type silicon by electrochemical etching through the optimization of the hydrogen fluoride (HF)/organic electrolyte composition and the design of the mask pattern. The electrochemical etching of p-type silicon in the HF: dimethylsulfoxide (DMSO): deionized (DI) water = 1:5:5 electrolyte can control the velocity of a reaction between an electrolyte and a hole necessary for the electrochemical etching of silicon through the mixing of the protic property of DI water and the aprotic property of DMSO. In this study, we fabricated a p-type silicon nanorod array of three-dimensional structures with an approximately 350 nm diameter from macroporous Si by applying two-step currents (40 mA, 200 s + 38 mA, 1600 s) to a 1.8 cm2 circular area using an optimized HF: DMSO: DI water = 1:5:5 electrolyte composition.

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Section: Resultsmentioning

confidence: 99%

Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon

Kim

Lyu

et al. 2010

Jpn. J. Appl. Phys.

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“…Comparison with the previous work.-We reported that ordered macropore formation is strongly based upon the interval of pre-etch pits. 13 Using substrates patterned with 8, 5, and 3 m intervals, ordered macropores were formed, while with 2 m, disordered macropores were obtained at 13 mA cm −2 . One of the important insights to understand the effect of the prepattern interval on ordered macropore formation is highlighted based on the results of the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Our previous study on the formation of ordered macropores starting from pre-etched substrates having different intervals revealed that ordered macropores were obtained when the intervals between pre-etch pits were 3, 5, and 8 m, while pore walls collapsed, and ordered macropores were not obtained with a 2 m interval wafer. 13 The diameter and wall thickness of the ordered macropores showed a tendency to decrease with a decrease in the interval of pre-etch pits, which could not be explained by considering the width of the space-charge region. 7 In the previous experiment, the size of the etch pits was kept constant, while the interval of the pre-etch pits was varied.…”

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confidence: 85%

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Ordering and Disordering of Macropores Formed in Prepatterned p-Type Silicon

Okayama¹,

Fukami²,

Plugaru³

et al. 2010

J. Electrochem. Soc.

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Macropore formation in prepatterned p-type silicon was conducted. Pre-etch pits with 4×4 and 1×1μm were prepared before anodization of silicon. Using the prepatterned silicon, the effect of applied current density on the ordering of macropores was investigated. The pattern size and the current density greatly affected the pore formation behavior. The ordering and disordering of macropores formed in p-type silicon were discussed by taking account of the electric field in silicon. The distortion of the electric field near the pre-etch pits depended on the size of the pre-etch pits. The effect of applied current density on the pore formation was explained by the gradient of the electric field or the local current distribution near the growing fronts. On the basis of this understanding, silicon nanowire formation was also demonstrated.

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“…Particularly, the fabricated PSi films/layers via the galvanostatic approach are often produced by the electrochemical etching of silicon in hydrofluoric acid-based electrolyte mixed with some surfactant like ethanol, and the starting silicon wafer is a single crystalline substrate, which would lead to the formation of various pore arrays with nano/microporous silicon features [7][8][9][10][11][12]. Such a wide range of pore sizes and morphologies was reported to be dependent greatly on the electrolyte concentration of fluoride ions, solution pH, the applied anodic current intensity, the use of organic additives, operating temperature, the silicon wafer characteristics (p-type or n-type silicon with crustal orientation) and whether the electrochemical anodization is being conducted in the dark or under the illumination [13,14]. In addition to this, the etching time was found to be the main factor to control and determine the produced pore length (the thickness of PSi layer).…”

Section: Introductionmentioning

confidence: 99%

Mesoporous Silicon with Nanostructured Au-Ti Front-side Electrical Contact as Efficient Capacitive Sensor Toward Different Alcohols in Liquid Phase

Harraz

Rashed

Alkorbi

et al. 2021

International Journal of Materials Technology and Innovation

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A novel capacitive sensor using mesoporous silicon (PSi) layer with a front electrical contact composed of Au-Ti nanostructure for sensitive detection of a group of alcohols in the liquid phase is designed and demonstrated. The PSi layer was firstly synthesized by the photo-electrochemical anodization of single crystalline n-type Si wafer in hydrofluoric acid based etching solution. The electrical contact was smoothly formed onto the front surface (directly exposed to the porous film) using Au-Ti nanocomposite by photolithographic technique and thermal evaporation approach. The as-fabricated PSi-Au-Ti electrical sensor exhibits efficient sensing response with a reversible behavior during the direct exposure and infiltration with liquid methanol and ethanol. However, the response toward propanol and butanol was less efficient and irreversible. The newlydeveloped electrical sensor was found efficient and promising also for the detection of pure water, which is advantageous for the future sensing ability of aqueous solutions. The observed change in capacitance during the sensing response is related to the generation of a local electrical field at the PSi interface, which led to a shift in the energy level of surface states, generating a modified space-charge region and finally affected the energy distribution and capacitance change.

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Macropore growth in a prepatterned p‐type silicon wafer

Cited by 21 publications

References 15 publications

Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon

Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon

Ordering and Disordering of Macropores Formed in Prepatterned p-Type Silicon

Mesoporous Silicon with Nanostructured Au-Ti Front-side Electrical Contact as Efficient Capacitive Sensor Toward Different Alcohols in Liquid Phase

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