An experimental and theoretical study of the formation and microstructure of porous silicon

Beale, M.I.J.; Benjamin, J. D.; Uren, Michael J.; Chew, N. G.; Cullis, A. G.

doi:10.1016/0022-0248(85)90029-6

Cited by 519 publications

(266 citation statements)

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“…As for porous Si, there exist two different models, namely "the Beale model" [32] and "the diffusion-limited model" [33] according to a review by Smith and Collins [19]. The former stresses the effect of electric field like that in the "tree" formation in electrostatic breakdown of solid-state insulators.…”

Section: Mechanism Of Nanopore Formationmentioning

confidence: 99%

Electrochemical processes for formation, processing and gate control of III–V semiconductor nanostructures

Hasegawa

Sato

2005

Electrochimica Acta

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This paper reviews recent efforts by authors' group to utilize electrochemical processes for formation, processing and gate control of III-V semiconductor nanostructures. Topics include precise photo anodic and pulsed anodic etching of InP, formation of arrays of <001>-oriented straight nanopores in n-type (001) InP by anodization and their possible applications, and macroscopic and nanometer-scale metal contact formation on GaAs, InP and GaN by a pulsed in-situ electrochemical process, which remarkably reduces Fermi level pinning. All the results indicate that electrochemical processes can achieve unique and important results which the conventional semiconductor technology cannot realize, anticipating their increased importance in future semiconductor nanotechnology and nanoelectronics. Key words:III-V semiconductors, anodic etching, nanopore, electrodeposition, Schottky barrier 1.IntroductionIt is widely recognized that artificial semiconductor nanostructures such as quantum wires (QWRs) and quantum dots(QDs) give rise to new rich functionalities to materials. They produce new quantum state spectra with novel state transitions and linear and non-linear quantum transport phenomena, and open up opportunities for novel quantum devices which control quantum-mechanical behavior of electrons and photons in various sophisticated ways.The standard approach for semiconductor nanostructure formation is to use fine crystal growth techniques such as molecular beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOVPE). To fabricate devices, various standard etching and metal deposition techniques are used together with standard lithography techniques. However, the electrochemical approaches, if it attains sufficiently high controllability at the nanometerscale, seems to be highly useful for nanostructure formation and processing. The expected advantages include: (1) process simplicity and versatility, (2) capability of self-organization, (3) low processing temperature, (4) low process induced damage, (5) precise electrical control and (6) low processing costs.Some well known examples are porous Si formation [1,2] and use of anodized alumina as nanostructure templates for formation of carbon nanotubes [3].The purpose of this paper is to review recent attempts by the authors' group at RCIQE, Hokkaido University, that have been carried out in order to investigate feasibility of utilizing electrochemical processes for nanometer-scale processing and nanostructure formation in III-V semiconductors. Topics discussed in this paper include controlled (1) anodic etching of InP,

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Section: Mechanism Of Nanopore Formationmentioning

confidence: 99%

Electrochemical processes for formation, processing and gate control of III–V semiconductor nanostructures

Hasegawa

Sato

2005

Electrochimica Acta

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“…7,8 In general, it is discussed and accepted in the literature that holes (h+) are required for both electropolishing and pores formation, where two hydrogen atoms are evolved for Morphological and Optical Characteristics of Porous Silicon Produced by Anodization Process J. Braz. Chem.…”

Section: Introductionmentioning

confidence: 99%

“…7,8 In general, it is discussed and accepted in the literature that holes (h+) are required for both electropolishing and pores formation, where two hydrogen atoms are evolved for each dissolved Si atom. 7 As a consequence, for the pore formation process, the current efficiencies are due to two electrons per dissolved Si atom, whereas four electrons are necessary for the electropolishing regime.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…7 As a consequence, for the pore formation process, the current efficiencies are due to two electrons per dissolved Si atom, whereas four electrons are necessary for the electropolishing regime. 8,9 In this sense, the global anodic half-reactions during the pore formation may be written as: 7Si + 6HF H 2 SiF 6 + H 2 + 2H + + 2e and during electropolishing as: 7Si + 6HF H 2 SiF 6 + 4H + + 4eThe final and stable product for Si in HF for both cases is H 2 SiF 6 or some of its ionized forms. This means that during the pore formation only two of the four available Si electrons participate in an interfacial charge transfer, while the remaining two electrons undergo corrosive hydrogen liberation.…”

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confidence: 99%

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Morphological and optical characteristics of porous silicon produced by anodization process in HF-acetonitrile and HF-ethanol solutions

Miranda¹,

Baldan²,

Beloto³

et al. 2008

J. Braz. Chem. Soc.

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Amostras de silício poroso (PS) foram obtidas pelo processo de anodização em lâminas de Si tipo n, dopadas com fósforo. A oxidação eletroquímica do PS foi obtida utilizando-se solução de ácido fluorídrico (HF) contendo aditivos como etanol e acetonitrila (MeCN). A formação dos poros foi estudada com a variação da resistividade das laminas de Si e parâmetros de processo como: concentração do ácido, densidade de corrente e tempo de anodização. As técnicas de Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Espalhamento Raman foram utilizadas para a investigação da morfologia e fotoluminescência, respectivamente. A camada de PS formada com o uso da solução de HF-MeCN mostrou maior uniformidade e homogeneidade na distribuição dos macroporos com diferentes tipos e tamanhos. Esse comportamento pode ser explicado devido a tensão superficial da MeCN ser maior que a do etanol. Consequentemente, as moléculas de MeCN podem passivar a superfície do silício durante o processo de anodização.Porous silicon (PS) samples were obtained by anodization etching process of n-type silicon wafer phosphorus-doped. Electrochemical oxidation of PS was investigated in aqueous hydrofluoric acid (HF) containing additive such as ethanol or acetonitrile. Pore formation was studied with the variation of type and resistivity of the silicon wafer, taking into account the most important anodization process parameters such as: acid concentration, current density and anodization time. Scanning Electron Microscopy (SEM) and Raman Scattering Spectroscopy measurements were used to characterize the macropore morphology changes and sample photoluminescense responses, respectively. PS layer formed in HF-acetonitrile solution showed more uniform and homogeneous macropore distributions with different shapes and sizes. Behavior may be explained because acetonitrile surface tension is greater than that of ethanol. Therefore, acetonitrile molecules might passivate the silicon surface dissolved during the anodization process. Keywords: porous silicon, HF-acetonitrile, HF-ethanol IntroductionSince the discovery of its visible photoluminescence (PL) at room temperature, porous silicon (PS) has been intensively studied. Nowadays, PS is considered a very attractive material for the sensing layer in a chemical sensor, sacrificial layer in micromachining, and light emitting diode (LED) in optoelectronic devices. [1][2][3][4] Porous Si might be formed by electrochemical etching of single monocrystalline Si in HF solutions containing additives as ethanol or acetonitrile (MeCN). However, the anodization process was firstly studied by Bomchil et al., 5 in 1983, using HF and ethanol solution and they reported that ethanol improved the homogeneity of PS layer. Consequently, HF-ethanol has been used by most research groups as the standard electrolyte for PS formation process. After that, Propst et al. 6 have reported the electrochemical oxidation of p-and n-type silicon in nonaqueous electrolyte of HF-MeCN and discussed their singular and large porous structure...

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Alkylierung von porösem Silicium durch direkte Umsetzung mit Alkenen und Alkinen

et al. 1998

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An experimental and theoretical study of the formation and microstructure of porous silicon

Cited by 519 publications

References 10 publications

Electrochemical processes for formation, processing and gate control of III–V semiconductor nanostructures

Electrochemical processes for formation, processing and gate control of III–V semiconductor nanostructures

Morphological and optical characteristics of porous silicon produced by anodization process in HF-acetonitrile and HF-ethanol solutions

Alkylierung von porösem Silicium durch direkte Umsetzung mit Alkenen und Alkinen

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