Three-dimensional etching of silicon for the fabrication of low-dimensional and suspended devices

Walavalkar, Sameer S.; Homyk, Andrew; Henry, Michael David; Scherer, Axel

doi:10.1039/c2nr32981f

Cited by 13 publications

(13 citation statements)

References 16 publications

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“…Silicon is chosen as the mold material for its wide availability and varieties of relevant fabrication processes. In particular, recent developments in silicon dry etching produce smooth sidewall profiles [47][48][49] where the outside layer of the rough Si on the mold is converted to SiO2 during the thermal oxidation and subsequently removed by the BHF. After this treatment, the Si mold sidewall roughness is significantly reduced [50].…”

Section: Fabricationmentioning

confidence: 99%

Imprinted Polymer Microrings as High-Performance Ultrasound Detectors in Photoacoustic Imaging

Zhang

Chen

Ling

et al. 2015

J. Lightwave Technol.

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Development of both fundamental research and clinical applications of photoacoustic imaging callfor ultrasound detectors of high sensitivity, flat frequency response and compact size, which are not easily satisfied by traditional ultrasound detectors. Therefore, many alternative ultrasound detectors have been investigated in recent years and a representative one is the imprinted polymer microring resonator based detector. This review covers its principle, device fabrication, characterization and application, with an emphasis on how the microring's unique properties make it act as a high performance ultrasound detector in photoacoustic imaging systems. The imprinted polymer microring has high detection sensitivity, broadband frequency response, compact size and good operation robustness. Application of microrings in photoacoustic tomography generates truthful reconstructed images; use of microring in photoacoustic microscopy leads to improved image resolution; the detector's compact size makes it promising for photoacoustic endoscopic applications. When integrated with other electromagnetic wave absorbers, novel applications such as real-time terahertz pulse detection can be realized. 0733-8724 (c)reduced scattering and attenuation of the acoustic wave than its optical counterpart [1,17]. What is more, PAI can be combined with ultrasound imaging [19][20][21][22][23] or fluorescence imaging [23-26] to achieve complementary details to each other.Ultrasound detectors play a vital role in PAI. For example, in photoacoustic microscopy, its axial resolution is inversely proportional to the detector bandwidth and can be estimated by: R = 0.88 c/BW, where R is the axial resolution, c the sound speed, and BW the detector's bandwidth [27]. Since c is a constant in most soft biological tissues, R is primarily determined by the detector's bandwidth. As an another example, for truthful image reconstructions in the photoacoustic tomography, both high frequency signals generated from the sharp parts of the object and low frequency signals from the smooth parts of the object need to be collected efficiently [28].This requires an ultrasound detector with broadband response covering both low and high frequencies. Piezoelectric transducers have been the most commonly used ultrasound detector in PAI [29,30]. They are usually operated over a band of frequencies centered at their resonant frequencies where the thickness of the piezoelectric crystal equals to half of the detected acoustic wavelength. As a result, high-frequency transducers require thin crystals, which impose demanding fabrication challenges and robustness issues. Thus, the axial resolution in the photoacoustic microscopy stays around 15-20 µm [26,31], and is one order of magnitude worse than the lateral resolution achieved by fine laser focusing [32,33]. Moreover, a broad acoustic bandwidth covering nearly DC to very high frequencies, which is essential to truthful image reconstructions, is highly restricted due to the characteristic of this resonance effect. What is mo...

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Section: Fabricationmentioning

confidence: 99%

Imprinted Polymer Microrings as High-Performance Ultrasound Detectors in Photoacoustic Imaging

Zhang

Chen

Ling

et al. 2015

J. Lightwave Technol.

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“…Three dimensional (3D) silicon micro-and nanomachining has attracted a lot of interest in recent years for both research and industrial uses, and several promising applications have been proposed and demonstrated, e.g. vertically stacked silicon nanowires for field effect transistors (FET) [1], unified memory [2] and biosensors [3], shape-modified silicon nanopillars for quantum transport study [4] and FET [5], 3D silicon single cubic structures for 3D photonic crystal structures [6], etc. However, to easily fabricate 3D micro-and nanostructures, and simultaneously obtain a good size and shape control of the fabricated structures, is still considered to be difficult.…”

Section: Introductionmentioning

confidence: 99%

DREM2: a facile fabrication strategy for freestanding three dimensional silicon micro- and nanostructures by a modified Bosch etch process

Chang

Jensen

Hübner

et al. 2018

J. Micromech. Microeng.

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“…These nanopillars were fully converted into SiO 2 prior to their embedment in metal and into a suspended membrane. Upon modification of the applied (deep) reactive ion etch settings, the silicon nanopillars can have vertical or sculptured sidewalls [12][13][14], where the latter allows for the formation of quantum dots [13]. While in previous work Si pillars were converted into glass, in our contribution non-sculptured silicon nanopillars in combination conformal deposition steps, corner lithography [15][16] and sacrificial etch steps are applied to realize SiRNbased membranes containing massive arrays of parallel, hollow nanopores with embedded nano-cages.…”

Section: Introductionmentioning

confidence: 99%

Wafer-scale nanostructure formation inside vertical nano-pores

Berenschot

Sun

Tiggelaar

et al. 2017

2017 IEEE 12th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS)

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We propose a wafer-scale technique for nanostructure formation inside vertically oriented, throughmembrane nano-pores. It uses 50 nm monocrystalline silicon pillars as a mold, embedded in a silicon nitride membrane formed in an innovative step. The proposed technique paves the way towards advanced functionalization of parallel oriented nano-pores for actuation, sensing, filtering/trapping purposes.

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Three-dimensional etching of silicon for the fabrication of low-dimensional and suspended devices

Cited by 13 publications

References 16 publications

Imprinted Polymer Microrings as High-Performance Ultrasound Detectors in Photoacoustic Imaging

Imprinted Polymer Microrings as High-Performance Ultrasound Detectors in Photoacoustic Imaging

DREM2: a facile fabrication strategy for freestanding three dimensional silicon micro- and nanostructures by a modified Bosch etch process

Wafer-scale nanostructure formation inside vertical nano-pores

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