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Showing papers on "Isotropic etching published in 2006"


Journal ArticleDOI
10 Nov 2006-Science
TL;DR: A gas-phase plasma hydrocarbonation reaction is presented to selectively etch and gasify metallic nanotubes, retaining the semiconducting nanot tubes in near-pristine form and is scalable and compatible with existing semiconductor processing for future integrated circuits.
Abstract: Metallic and semiconducting carbon nanotubes generally coexist in as-grown materials We present a gas-phase plasma hydrocarbonation reaction to selectively etch and gasify metallic nanotubes, retaining the semiconducting nanotubes in near-pristine form With this process, 100% of purely semiconducting nanotubes were obtained and connected in parallel for high-current transistors The diameter- and metallicity-dependent "dry" chemical etching approach is scalable and compatible with existing semiconductor processing for future integrated circuits

540 citations


Journal ArticleDOI
TL;DR: In this paper, the combination of femtosecond laser dielectric modification and selective chemical etching was used to fabricate high-quality microchannels in glass, and the optimum irradiation conditions needed to produce high-aspect ratio micro-channels with small symmetric cross-sections and smooth walls.
Abstract: We use the combination of femtosecond laser dielectric modification and selective chemical etching to fabricate high-quality microchannels in glass. The photoinduced modification morphology has been studied in fused silica and in borosilicate glass BK7, using ultra-high spatial resolution techniques of selective chemical etching followed by atomic force or scanning electron microscopy. The analysis shows that the high differential etch rate inside the modified regions, is determined by the presence of polarization-dependent self-ordered periodic nanocracks or nanoporous structures. We also investigate the optimum irradiation conditions needed to produce high-aspect ratio microchannels with small symmetric cross-sections and smooth walls.

275 citations


Journal ArticleDOI
TL;DR: A new procedure for fabricating fused-silica emitters for electrospray ionization-mass spectrometry (ESI-MS) in which the end of a bare fused- silica capillary is immersed into aqueous hydrofluoric acid, and water is pumped through the capillary to prevent etching of the interior.
Abstract: We have developed a new procedure for fabricating fused-silica emitters for electrospray ionization-mass spectrometry (ESI-MS) in which the end of a bare fused-silica capillary is immersed into aqueous hydrofluoric acid, and water is pumped through the capillary to prevent etching of the interior Surface tension causes the etchant to climb the capillary exterior, and the etch rate in the resulting meniscus decreases as a function of distance from the bulk solution Etching continues until the silica touching the hydrofluoric acid reservoir is completely removed, essentially stopping the etch process The resulting emitters have no internal taper, making them much less prone to clogging compared to, eg, pulled emitters The high aspect ratios and extremely thin walls at the orifice facilitate very low flow rate operation; stable ESI-MS signals were obtained for model analytes from 5-μm-diameter emitters at a flow rate of 5 nL/min with a high degree of interemitter reproducibility In extensive evaluatio

238 citations


Journal ArticleDOI
TL;DR: In this article, superhydrophobic surfaces were fabricated on silicon by nano-imprint lithography and wet chemical etching, and glass molds were used to imprint a positive photoresist layer.

221 citations


Journal ArticleDOI
TL;DR: Three-dimensional microstructured medical devices, including microneedles and tissue engineering scaffolds, were fabricated by two photon induced polymerization of Ormocer organic-inorganic hybrid materials to suggest that two photon inducing polymerization is able to create medical microdevices with a larger range of sizes, shapes, and materials than conventional microfabrication techniques.

202 citations


Patent
15 May 2006
TL;DR: In this article, the authors present an approach for etching semiconductor wafers and the like in which a substrate is supported by a pedestal within a chamber, and at least one gas capable of etching the substrate or a film material on the substrate is introduced into the chamber through a segmented gas injection element which is separated from the substrate by a distance approximately less than its size from which the distribution of the flow or mixture of gas can be altered spatially proximate to the substrate in a controlled and variable way.
Abstract: Apparatus and process for etching semiconductor wafers and the like in which a substrate is supported by a pedestal within a chamber, and at least one gas capable of etching the substrate or a film material on the substrate is introduced into the chamber through a segmented gas injection element which is separated from the substrate by a distance approximately less than its size from which the distribution of the flow or mixture of gas can be altered spatially proximate to the substrate in a controlled and variable way, for each wafer or substrate if desired, by having a varying amount or mixture of gas flow to some or all of the segments such as to cause the etching rate distribution to vary across the substrate.

192 citations


Journal ArticleDOI
TL;DR: In this article, a method involving dry deposition plus wet chemical etching was devised to fabricate silicon nanowire (SiNW) arrays and to study silver catalysis during fabrication.
Abstract: A method involving dry deposition plus wet chemical etching was devised to fabricate silicon nanowire (SiNW) arrays and to study silver catalysis during fabrication. Through investigation of the track of catalyst particles, it was shown that Ag really catalyses the etching of silicon underneath Ag, which clarifies doubts about the formation of SiNW arrays during wet chemical etching. The intrinsic properties of Ag and the network structure of Ag clusters during etching facilitate the etching process. The etching product, i.e. vertical SiNW arrays containing an Ag nanocluster mesh, could be considered as a prototype secondary composite nanostructured catalyst with promise for future applications.

181 citations


Patent
27 Jan 2006
TL;DR: In this article, a method for treating a silicon-containing surface is provided which includes removing contaminants and smoothing the substrate surface by a slow etch process (e.g., about 100 A/min).
Abstract: In one embodiment, a method for treating a silicon-containing surface is provided which includes removing contaminants and/or smoothing the substrate surface by a slow etch process (e.g., about 100 A/min) is provided which includes removing silicon material while forming a recess within a source/drain (S/D) area on the substrate surface. In another embodiment, a method for cleaning a process chamber is provided which includes exposing the interior surfaces with a chamber clean gas that contains an etchant and a silicon source. The chamber clean process limits the etching of quartz and metal surfaces within the process chamber.

176 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a systematic experimental investigation of the reactions between hydrogen plasma and single-walled carbon nanotubes (SWNTs) at various temperatures, and investigate the properties of SWNTs after hydrogenation.
Abstract: We present a systematic experimental investigation of the reactions between hydrogen plasma and single-walled carbon nanotubes (SWNTs) at various temperatures. Microscopy, infrared (IR) and Raman spectroscopy, and electrical transport measurements are carried out to investigate the properties of SWNTs after hydrogenation. Structural deformations, drastically reduced electrical conductance, and an increased semiconducting nature of SWNTs upon sidewall hydrogenation are observed. These changes are reversible upon thermal annealing at 500 °C via dehydrogenation. Harsh plasma or high temperature reactions lead to etching of nanotubes likely via hydrocarbonation. Smaller SWNTs are markedly less stable against hydrocarbonation than larger tubes. The results are fundamental and may have implications to basic and practical applications including hydrogen storage, sensing, band gap engineering for novel electronics, and new methods of manipulation, functionalization, and etching of nanotubes.

166 citations


Patent
26 Jan 2006
TL;DR: In this paper, a method for etching a chromium layer is described, which is particularly suitable for fabricating photomasks and can be used for plasma etching of chromium layers.
Abstract: A method for etching a chromium layer is provided herein. In one embodiment, a method for etching a chromium layer includes providing a filmstack in an etching chamber, the filmstack having a chromium layer partially exposed through a patterned layer, providing at least one halogen containing process gas to a processing chamber, biasing the layer disposed on a substrate support in the processing chamber with a plurality of power pulses less than 600 Watts, and etching the chromium layer through a patterned mask. The method for plasma etching a chromium layer described herein is particularly suitable for fabricating photomasks.

154 citations


Patent
17 May 2006
TL;DR: In this paper, a method of fabricating nano-tips involves placing a precursor nanotip with an apex and shank in a vacuum chamber, optionally applying an electric field to the precursor to remove oxide and other contaminant species, and subsequently admitting an etchant gas to the vacuum chamber to perform field assisted etching by preferential adsorption.
Abstract: A method of fabricating nano-tips involves placing a precursor nanotip with an apex and shank in a vacuum chamber; optionally applying an electric field to the precursor nanotip to remove oxide and other contaminant species; subsequently admitting an etchant gas to the vacuum chamber to perform field assisted etching by preferential adsorption of the etchant gas on the shank; and gradually reducing the applied electric field to confine the adsorption of the etchant gas to the shank as etching progresses.

Patent
16 Oct 2006
TL;DR: An etching solution for silicon oxide may be used in a process for enlarging an opening formed through a silicon oxide layer as mentioned in this paper, which may etch the silicon oxide without damage to a metal silicide layer exposed by the opening.
Abstract: An etching solution for silicon oxide may be used in a process for enlarging an opening formed through a silicon oxide layer. The etching solution includes about 0.2 to about 5.0 percent by weight of a hydrogen fluoride solution, about 0.05 to about 20.0 percent by weight of an ammonium fluoride solution, about 40.0 to about 70.0 percent by weight of an alkyl hydroxide solution and remaining water. The etching solution may etch the silicon oxide layer without damage to a metal silicide layer exposed by the opening.

Journal ArticleDOI
TL;DR: In this paper, high conductive and transparent aluminum-doped zinc oxide (ZnO:Al) films were prepared by reactive mid-frequency (MF) magnetron sputtering at high growth rates.

Journal ArticleDOI
TL;DR: In this article, the same femtosecond laser, with different irradiation parameters, was used to fabricate high quality optical waveguides on the same substrate, enabling the integration of micro-channel and waveguide will enable a forthcoming class of biophotonic sensors.
Abstract: We report on the fabrication of microfluidic channels in fused silica using femtosecond laser irradiation followed by chemical etching. Using an astigmatically shaped beam, we achieve microchannels with circular cross section and length up to 1.5mm. We use the same femtosecond laser, with different irradiation parameters, to fabricate high quality optical waveguides on the same substrate. The integration of microchannels and waveguides will enable a forthcoming class of biophotonic sensors.

Journal ArticleDOI
TL;DR: The unusual structure on the surface, which has a binary structure consisted of microprotrusions and nanoparticles, plays a very vital role in constructing of the stable biomimetic superhydrophobic surface on aluminum alloy.

Patent
21 Dec 2006
TL;DR: In-situ etching of the source drain recess for replacement source-drain applications provides several advantages over state-of-the-art ex-Situ etch as discussed by the authors.
Abstract: This invention adds to the art of replacement source-drain cMOS transistors. Processes may involve etching a recess in the substrate material using one equipment set, then performing deposition in another. Disclosed is a method to perform the etch and subsequent deposition in the same reactor without atmospheric exposure. In-situ etching of the source-drain recess for replacement source-drain applications provides several advantages over state of the art ex-situ etching. Transistor drive current is improved by: (1) Eliminating contamination of the silicon-epilayer interface when the as-etched surface is exposed to atmosphere and (2) Precise control over the shape of the etch recess. Deposition may be done by a variety of techniques including selective and non-selective methods. In the case of blanket deposition, a measure to avoid amorphous deposition in performance critical regions is also presented.

Journal ArticleDOI
TL;DR: In this paper, ZnO:Al 2 O 3 targets were prepared on glass substrates by RF and DC sputtering from ceramic targets, showing a weak dependence on film thickness and substrate temperature while a strong dependence on sputter pressure.

Patent
18 Sep 2006
TL;DR: In this article, a method for the plasma-free etching of silicon using the etching gas ClF 3 or XeF 2 and its use is provided, where the silicon is provided having one or more areas to be etched as a layer on the substrate or as the substrate material itself.
Abstract: A method for the plasma-free etching of silicon using the etching gas ClF 3 or XeF 2 and its use are provided. The silicon is provided having one or more areas to be etched as a layer on the substrate or as the substrate material itself. The silicon is converted into the mixed semiconductor SiGe by introducing germanium and is etched by supplying the etching gas ClF 3 or XeF 2 . The introduction of germanium and the supply of the etching gas ClF 3 or XeF 2 may be performed at the same time or alternatingly. In particular, it is provided that the introduction of germanium be performed by implanting germanium ions in silicon.

Patent
06 Sep 2006
TL;DR: In this article, a method for selectively etching a high k layer with respect to a silicon-based material is provided, where the high k layers are placed into an etch chamber.
Abstract: A method for selectively etching a high k layer with respect to a silicon based material is provided. The high k layer is placed into an etch chamber. An etchant gas is provided into the etch chamber, wherein the etchant gas comprises H2. A plasma is generated from the etchant gas to selectively etch the high k layer with respect to a silicon based material.

Journal ArticleDOI
TL;DR: In this paper, aluminum doped zinc oxide (ZnO:Al, AZO) films were prepared by reactive mid frequency magnetron sputtering and characterized the electrical and optical properties as well as surface morphology obtained after wet chemical etching.

Patent
31 Mar 2006
TL;DR: In this article, a GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate, which can be used as a template substrate for fabricating GaN based light emitting diode or laser diode.
Abstract: A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.

Patent
Taeho Shin1, Jingbao Liu1, Ajey M. Joshi1, Jong Mun Kim1, Wei-Te Wu1 
18 Apr 2006
TL;DR: In this article, a method of removing a silicon-containing hard polymeric material from an opening leading to a recessed feature during the plasma etching of said recessed features into a carbon-containing layer in a semiconductor substrate is described.
Abstract: A method of removing a silicon-containing hard polymeric material from an opening leading to a recessed feature during the plasma etching of said recessed feature into a carbon-containing layer in a semiconductor substrate. The method comprises the intermittent use of a cleaning step within a continuous etching process, where at least one fluorine-containing cleaning agent species is added to already present etchant species of said continuous etching process for a limited time period, wherein the length of time of each cleaning step ranges from about 5% to about 100% of the time length of an etch step which either precedes or follows said cleaning step.

Journal ArticleDOI
Meiwen Cao1, Xiaoyan Song1, Jin Zhai1, Jinben Wang1, Yilin Wang1 
TL;DR: The results show that wettability and reflectivity of these surfaces strongly depend on the etching method and the resultant surface morphology, and the porous silicon surface produced by thin Pt-assisted acidic etching presents abundant holes and particles with diameters ranging from nanometers to submicrometers.
Abstract: Highly antireflective porous silicon surfaces with superhydrophobicity were obtained by means of chemical etching and fluoroalkylsilane self-assembly. The results show that wettability and reflectivity of these surfaces strongly depend on the etching method and the resultant surface morphology. All of the four resultant porous silicon surfaces by alkaline etching, acidic etching, thick Pt-assisted acidic etching, and thin Pt-assisted acidic etching can reduce reflectance, but the efficiency differs greatly. Except for the alkaline etching, the porous silicon surfaces produced by the other three etching methods can reach superhydrophobicity after fluoroalkylsilane modification. These differences are due to the different surface morphology and roughness. Moreover, the porous silicon surface produced by thin Pt-assisted acidic etching presents abundant holes and particles with diameters ranging from nanometers to submicrometers. This morphology enables the porous silicon surface to own a very low reflectance value that is averaged to be about 3% over the whole experimental photon wavelength spanning 300-800 nm.

Patent
29 Jun 2006
TL;DR: In this article, a field effect transistor is formed as follows: a trench is formed in a semiconductor region, and a dielectric layer lining the trench sidewalls and bottom is formed.
Abstract: A field effect transistor is formed as follows. A trench is formed in a semiconductor region. A dielectric layer lining the trench sidewalls and bottom is formed. The trench is filled with a conductive material. The conductive material is recessed into the trench to thereby form a shield electrode in a bottom portion of the trench. The recessing of the conductive material includes isotropic etching of the conductive material. An inter-electrode dielectric (IED) is formed over the recessed shield electrode.

Patent
23 Feb 2006
TL;DR: In this paper, the authors proposed a method to dissipate charge build-up on a substrate being etched by plasma etching by generating a negative bias on the substrate surface relative to the plasma.
Abstract: Apparatus, systems and methods for plasma etching substrates are provided that achieve dissipation of charge build-up on a substrate being plasma etched to avoid notching or twisting in high aspect ratio contents and similar features. Charge build-up on a substrate being etched by plasma etching can be dissipated by a method for etching a substrate, the method comprising: providing a plasma processing chamber comprising a chamber enclosure and a substrate support adapted to support a substrate within the chamber enclosure; supporting a substrate on the substrate support; forming a plasma within the chamber enclosure such that a surface of the substrate is in contact with the plasma; etching the substrate by generating a negative bias on the substrate surface relative to the plasma; and intermittently changing the bias on the substrate surface to positive relative to the plasma. The present method can be integrated into known plasma processing systems.

Journal ArticleDOI
TL;DR: In this article, the authors measured the average pore size and pore volumes to estimate the width of the graphitic domain walls, δW, left behind by the etching process, which corresponds to the specimen with the highest surface area, approximately 1 nm, which is about equal to the total width of one graphene layer and two SiOmC4−m tetrahedra, one on either side of the graphene sheet.
Abstract: Etching polymer-derived silicon-oxycarbide ceramics with hydrofluoric acid creates nanoporous structures of specific surface areas as high as 600 m2/g. The change in composition upon etching shows the removal of silica, not carbon. The structure remaining after etching is postulated to consist of a scaffolding of graphene networks with their surfaces decorated with mixed bonds of tetrahedral silicon bonded to both oxygen and carbon (SiOmC4−m, where m=1, 2, or 3). The pores existing within such scaffoldings are presumed to have been filled with SiO2 tetrahedra, which are removed by etching. The measurement of the average pore size and pore volumes permits us to estimate the width of the graphitic domain walls, δW, left behind by the etching process. The smallest value of δW, which corresponds to the specimen with the highest surface area, is approximately 1 nm, which is about equal to the total width of one graphene layer and two SiOmC4–m tetrahedra, one on either side of the graphene sheet. This highest surface area specimen is also believed to have the largest size of the silica domains in the unetched samples. In specimens with smaller domains, the etching is only partially successful in removing the silica, presumably because their small size hinders the access of the etchant to the silica tetrahedra. The above behavior is found for samples with low to moderate carbon content. In one sample with a very high carbon content, the etching process removes some carbon as well as silica.

Patent
05 Jun 2006
TL;DR: In this paper, a deposition/etching/deposition process is provided for filling a gap in a surface of a substrate, where a liner is formed over the substrate so that distinctive reaction products are formed when it is exposed to a chemical etchant.
Abstract: A deposition/etching/deposition process is provided for filling a gap in a surface of a substrate. A liner is formed over the substrate so that distinctive reaction products are formed when it is exposed to a chemical etchant. The detection of such reaction products thus indicates that the portion of the film deposited during the first etching has been removed to an extent that further exposure to the etchant may remove the liner and expose underlying structures. Accordingly, the etching is stopped upon detection of distinctive reaction products and the next deposition in the deposition/etching/deposition process is begun.

Journal ArticleDOI
21 Aug 2006
TL;DR: In this paper, the authors reported the highest etch depth of annealed Pyrex glass achieved by wet etching in highly concentrated HF solution, using a low stress chromium-gold with assistance of photoresist as masking layer.
Abstract: This paper reports the highest etch depth of annealed Pyrex glass achieved by wet etching in highly concentrated HF solution, using a low stress chromium–gold with assistance of photoresist as masking layer. The strategies to achieve that are: increasing the etch rate of glass and simultaneously increasing the resistance of Cr/Au mask in the etchant. By annealing the Pyrex glass and using a highly concentrated HF acid, a high etch rate can be obtained. Furthermore, a method to achieve a good resistance of the Cr/Au masking layer in the etching solution is to control the residual stress and to increase the thickness of Au deposition up to 1 μm. In addition, the presence of a hard baked photoresist can improve the etching performance. As a result, a 500-μm thick Pyrex glass wafer was etched through.

Journal ArticleDOI
M. Steinert1, Jörg Acker1, Matthias Krause1, Steffen Oswald1, Klaus Wetzig1 
TL;DR: The role of intermediate species generated during wet chemical etching of silicon in a HF-rich HF/HNO3 mixture was studied by spectroscopic and analytical methods and a complex N(III) species (3NO+.NO3-) denoted as [N4O6(2+)] is observed in these solutions.
Abstract: The role of intermediate species generated during wet chemical etching of silicon in a HF-rich HF/HNO3 mixture was studied by spectroscopic and analytical methods at 1 °C. The intermediate N2O3 was identified by its cobalt blue color and the characteristic features in its UV−vis and Raman spectra. Furthermore, a complex N(III) species (3NO+·NO3-) denoted as [N4O62+] is observed in these solutions. The time-dependent decay of the N(III) intermediates, mainly by their oxidation at the liquid−air interface, serves as a precondition for the study of the etch rate as function of the intermediate concentration measured by Raman spectroscopy. From a linear relationship between etch rate and [N4O62+] concentration, NO+ is considered to be a reactive species in the rate-limiting step. This step is attributed to the oxidation of permanent existing Si−H bonds at the silicon surface by the reactive NO+ species. N2O3 serves as a reservoir for the generation of NO+ leading to a complete coverage of the silicon surface ...

Journal ArticleDOI
TL;DR: In this article, the authors used ion beam etching and wet chemical etching to obtain a maximum energy product of 90kJ∕m3 for the sputtered SmCo layers up to a thickness of 50μm.
Abstract: Efficient magnetic microactuators require a deposition and patterning of a permanent magnetic material. A material that can be deposited in the range of up to a couple of 10μm is sputtered SmCo. For the fabrication of magnetic microactuators, alternative substrate materials besides silicon are of great interest. Therefore, alumina-ceramic as well as B270-glass substrates were included in the investigation. A maximum energy product of 90kJ∕m3 was achieved for rather thick layers of 30μm deposited on glass or ceramic substrates. The latter substrates were found to be suitable for the deposition of SmCo layers up to a thickness of 50μm. Furthermore, the SmCo exhibits isotropic magnetic properties, thus a magnetization of the permanent magnetic layer can be performed in plane as well as perpendicular to the film plane. For the patterning of these thick SmCo layers ion beam etching and wet chemical etching were examined. For both methods, the suitability of patterning thick SmCo layers could be demonstrated. F...