431 results about "Electrochemical etching" patented technology

A field emission device having bundles of aligned parallel carbon nanotubes on a substrate. The carbon nanotubes are oriented perpendicular to the substrate. The carbon nanotube bundles may be up to 300 microns tall, for example. The bundles of carbon nanotubes extend only from regions of the substrate patterned with a catalyst material. Preferably, the catalyst material is iron oxide. The substrate is preferably porous silicon, as this produces the highest quality, most well-aligned nanotubes. Smooth, nonporous silicon or quartz can also be used as the substrate. The method of the invention starts with forming a porous layer on a silicon substrate by electrochemical etching. Then, a thin layer of iron is deposited on the porous layer in patterned regions. The iron is then oxidized into iron oxide, and then the substrate is exposed to ethylene gas at elevated temperature. The iron oxide catalyzes the formation of bundles of aligned parallel carbon nanotubes which grow perpendicular to the substrate surface. The height of the nanotube bundles above the substrate is determined by the duration of the catalysis step. The nanotube bundles only grow from the patterned regions.

Ion source and method of making and sharpening. The ion source is a single crystal metal conductor having a substantially conical tip portion with substantial rotational symmetry. The tip portion terminates with a tip radius of curvature in the range of 50-100 nanometers. The ion source is made by electrochemical etching so that a conical tip of a selected geometry is formed. The ion source is then sharpened to provide a source of ions from a volume near the size of a single atom. Further, this ion source makes possible a stable and practical light ion microscope which will have higher resolution than existing scanning electron microscopes and scanning metal-ion microscopes.

Si-doped porous GaN is fabricated by UV-enhanced Pt-assisted electrochemical etching and together with a low-temperature grown buffer layer are utilized as the template for InGaN growth. The porous network in GaN shows nanostructures formed on the surface. Subsequent growth of InGaN shows that it is relaxed on these nanostructures as the area on which the growth takes place is very small. The strain relaxation favors higher indium incorporation. Besides, this porous network creates a relatively rough surface of GaN to modify the surface energy which can enhance the nucleation of impinging indium atoms thereby increasing indium incorporation. It shifts the luminescence from 445 nm for a conventionally grown InGaN structure to 575 nm and enhances the intensity by more than two-fold for the growth technique in the present invention under the same growth conditions. There is also a spectral broadening of the output extending from 480 nm to 720 nm.

The invention discloses a process method for preparing an ultra-hydrophobic surface by the electrochemical method. The process adopts two processing steps: forming the micro nanometer double-structurerough surface by first electrochemical etching and then oxalic acid anodic oxidation; and preparing the ultra-hydrophobic surface by modifying the surface with fluorosilane. The method is simple andpractical, uses mature electrochemical etching and anodic oxidation technology, allows for easy mass production and avoids environmental pollution.

Highly uniform 1 nm silicon nanoparticles are provided by the invention. The nanoparticles exhibit beneficial properties. They are a source of stimulated emissions. They may be suspended in liquids, and solids. They can be formed into crystals, colloids and films. The nanoparticles of the invention are about 1 nm having about only one part in one thousand greater than 1 nm. A method for producing the silicon nanoparticle of the invention is a gradual advancing electrochemical etch of bulk silicon. Separation of nanoparticles from the surface of the silicon may also be conducted. Once separated, various methods may be employed to form plural nanoparticles into colloids, crystals, films and other desirable forms. The particles may also be coated or doped.

An attachment surface for an implantable device has an irregular pattern formed through a process including masking, chemical or electrochemical etching, blasting and debris removal steps. Surface material is removed from the implant surface without stress on the adjoining material and the process provides fully dimensional fillet radii at the base of the surface irregularities. This irregular surface is adapted to receive the ingrowth of bone material and to provide a strong anchor for that bone material which is resistant to cracking or breaking. The surface is prepared through an etching process which utilizes the random application of a maskant and subsequent etching in areas unprotected by the maskant. This chemical etching process is repeated a number of times as necessitated by the nature of the irregularities required in the surface. The blasting and debris removal steps produce microfeatures on the surface that enhance the ingrowth of bone material.

Conductivity-selective lateral etching of III-nitride materials is described. Methods and structures for making vertical cavity surface emitting lasers with distributed Bragg reflectors via electrochemical etching are described. Layer-selective, lateral electrochemical etching of multi-layer stacks is employed to form semiconductor/air DBR structures adjacent active multiple quantum well regions of the lasers. The electrochemical etching techniques are suitable for high-volume production of lasers and other III-nitride devices, such as lasers, HEMT transistors, power transistors, MEMs structures, and LEDs.

The invention is directed to methods for direct patterning of silicon. The invention provides the ability to fabricate complex surfaces in silicon with three dimensional features of high resolution and complex detail. The invention is suitable, for example, for use in soft lithography as embodiments of the invention can quickly create a master for use in soft lithography. In an embodiment of the invention, electrochemical etching of silicon, such as a silicon wafer, for example, is conducted while at least a portion of the silicon surface is exposed to an optical pattern. The etching creates porous silicon in the substrate, and removal of the porous silicon layer leaves a three-dimensional structure correlating to the optical pattern.

Methods of fabricating porous silicon by electrochemical etching and subsequent coating with a passivating agent process are provided. The coated porous silicon can be used to make anodes and batteries. It is capable of alloying with large amounts of lithium ions, has a capacity of at least 1000 mAh/g and retains this ability through at least 60 charge/discharge cycles. A particular pSi formulation provides very high capacity (3000 mAh/g) for at least 60 cycles, which is 80% of theoretical value of silicon. The Coulombic efficiency after the third cycle is between 95-99%. The very best capacity exceeds 3400 mAh/g and the very best cycle life exceeds 240 cycles, and the capacity and cycle life can be varied as needed for the application.

A method of manufacture for optical spectral filters with omnidirectional properties in the visible, near IR, mid IR and/or far IR (infrared) spectral ranges is based on the formation of large arrays of coherently modulated waveguides by electrochemical etching of a semiconductor wafer to form a pore array. Further processing of said porous semiconductor wafer optimizes the filtering properties of such a material. The method of filter manufacturing is large scale compatible and economically favorable. The resulting exemplary non-limiting illustrative filters are stable, do not degrade over time, do not exhibit material delamination problems and offer superior transmittance for use as bandpass, band blocking and narrow-bandpass filters. Such filters are useful for a wide variety of applications including but not limited to spectroscopy, optical communications, astronomy and sensing.

The present invention relates to a preparation method for a superamphiphobic surface of aluminum and an alloy thereof. According to the present invention, a two-step method is adopted to prepare a superhydrophobic surface, and a low surface energy material is adopted to modify the hydrophobic surface, wherein an electrochemical etching method is adopted to prepare an aluminum micron-scale rough surface, then a hydrothermal synthesis method is adopted to synthesize a zinc oxide micro-nano double rough structure, and the prepared superhydrophobic surface provides a contact angle of more than 156 DEG for water, and provides an oleophobic angle of more than 150 DEG C for lubricating oil; and the method has the following characteristics that: simpleness and practicality are provided, equipment requirements are low, the used electrochemical etching technology and the used hydrothermal synthesis technology are mature, the large-area superamphiphobic surface is easily prepared, and industrial manufacturing is easily achieved.

A textured surface and oxidation layer coating on a metallic material is accomplished through the chemical and/or electrochemical etching of the surface to modify the surface texture and an in-situ oxidation procedure. The surface is useful for the fabrication of prosthetic devices, particularly medical implants, due to the corrosion and wear resistance imparted by the oxidation layer and the ability to enhance grafting of the implant onto bone imparted by the surface texture.

Electrochemical etching tailors topography of a nanocrystalline or amorphous metal or alloy, which may be produced by any method including, by electrochemical deposition. Common etching methods can be used. Topography can be controlled by varying parameters that produce the item or the etching parameters or both. The nanocrystalline article has a surface comprising at least two elements, at least one of which is metal, and one of which is more electrochemically active than the others. The active element has a definite spatial distribution in the workpiece, which bears a predecessor spatial relationship to the specified topography. Etching removes a portion of the active element preferentially, to achieve the specified topography. Control is possible regarding: roughness, color, particularly along a spectrum from silver through grey to black, reflectivity and the presence, distribution and number density of pits and channels, as well as their depth, width, size. Processing parameters that have been correlated in the Ni—W system to topography features include, for both the deposition phase and the etching phase of a nanocrystalline surface: duty cycle, current density, deposition duration, plating chemistry, polarity ratio. The relative influence of the processing parameters can be noted and correlated to establish a relationship between values for processing parameters and degree of topography feature. Control can be established over the topography features. Correlation can be made for any such system that exhibits a definite spatial distribution of an active element that bears a predecessor spatial relationship to a desired topography feature.

Photoelectrochemical (PEC) etching is restricted to a group III nitride semiconductor-barrier interface to laterally etch or undercut the target group III nitride. The barrier interface is provided by the transparent sapphire substrate on which the target group III nitride is epitaxially grown or by a layer of material in intimate contact with the target group III nitride material and having a bandgap sufficiently high to make it resistant to PEC etching. Due to the first orientation in which this effect was first observed, it has been named backside-Illuminated photoelectrochemical (BIPEC) etching. It refers to a preferential etching at the semiconductor-barrier layer interface. The assembly can be exposed to light from any direction to effectuate bandgap-selective PEC etching. An opaque mask can be applied to limit the lateral extent of the photoelectrochemical etching.

Disclosed is a method of preparing a medical implant. The biocompatible metal surface of the implant is subjected to electrochemical etching in an electrolyte solution to which a current has been applied.

The invention discloses a method for manufacturing a gallium nitride-based light-emitting diode with a current barrier layer. The method comprises the following steps of: constituting a gallium nitride-based luminous epitaxial layer by using an n-type gallium nitride-based epitaxial layer, an active layer, a p-type gallium nitride-based epitaxial layer and an undoped gallium nitride-based epitaxial layer from top to bottom in turn on a sapphire substrate; defining a current blocking area on the gallium nitride-based luminous epitaxial layer and coating a metal layer serving as a mask on the undoped gallium nitride-based epitaxial layer of the current blocking area so as to cover the entire current blocking area; removing the undoped gallium nitride-based epitaxial layer outside the current blocking area by electrochemical etching; removing the metal layer serving as the mask; manufacturing a transparent conductive layer on the p-type gallium nitride-based epitaxial layer and the undoped gallium nitride-based epitaxial layer; and manufacturing a p electrode on the transparent conductive layer in the current blocking area. The current barrier layer is defined selectively by the electrochemical etching, so that the problems of damage and passivation caused by dry etching are solved and an undoped epitaxial layer-based gallium nitride-based light-emitting diode with current blocking effect is obtained.

An electrochemical etching cell (1) is proposed for etching an etching body (15) made at least superficially of an etching material. The etching cell (1) has at least one chamber filled with an electrolyte, and is provided with a first electrode (13), which at least superficially has a first electrode material, and with a second electrode (13') which at least superficially has a second electrode material. Furthermore, the etching body (15) is in contact, at least region-wise, with the electrolyte. In this context, the first electrode material and the second electrode material are selected such that, after the etching, the etching body (15) is not contaminated and/or is not impaired in its properties by the electrode materials. In particular, the electrode materials are the same materials as the etching material. Also proposed is a method for etching an etching body (15) using this etching cell (1), the first and/or the second electrode (13, 13') being used as a sacrificial electrode. The proposed etching cell is particularly suitable for etching silicon wafers in a CMOS-compatible production line.

A terminal for a Li-ion battery cell utilizes a bimetallic strip formed from the materials used as the Li-ion cell current collectors, such as copper and aluminum. The bimetallic strip is to be used as, at least one, of the Li-ion pouch cell terminals. At least one portion of the bimetallic strip has one of the metallic components removed by such means as chemical or electrochemical etching, mechanical milling, skiving, or grinding, the remaining component being connected to the collector and the other end of the strip serving as the terminal.

A method of forming an electron emitter includes the steps of: (i) forming a nanostructure-containing material; (ii) forming a mixture of nanostructure-containing material and a matrix material; (iii) depositing a layer of the mixture onto at least a portion of at least one surface of a substrate by electrophoretic deposition; (iv) sintering or melting the layer thereby forming a composite; and (v) electrochemically etching the composite to remove matrix material from a surface thereof, thereby exposing nanostructure-containing material.

The invention discloses a multi-potential electrolytic processing method, which is used for processing deep-hole deep-groove structures. The method comprises the following steps that a workpiece is arranged in an electrolytic bath; an inner electrode, an insulation layer covering the inner electrode and an outer electrode covering the insulation layer are arranged above the workpiece, and the lower end surface of the inner electrode is exposed and is used as a processing surface; three potentials are set, the outer electrode has high potential, the inner electrode has low potential, the potential of the workpiece is between the potential of the inner electrode and the potential of the outer electrode; the workpiece, the outer electrode and the inner electrode are electrically conducted through electrolyte; the outer electrode adopts inert conducting materials; the potential is regulated so that the high-potential region and the electrochemical etching reaction are concentrated in a region right under the low-potential electrode. The multi-potential electrolytic processing method has the advantages that the high potential of an insoluble auxiliary anode covers the outside of the cathode side wall insulation layer for restraining the electric field, the stray corrosion and the side wall taper during the electrolytic processing of structures such as holes, seams and grooves can be effectively controlled, better locality is realized, and narrow depth type straight wall deep groove structures can be processed.