2559 results about "Porous silicon" patented technology

A method and apparatus for depositing nano-porous low dielectric constant films by reaction of a silicon hydride containing compound or mixture optionally having thermally labile organic groups with a peroxide compound on the surface of a substrate. The deposited silicon oxide based film is annealed to form dispersed microscopic voids that remain in a nano-porous silicon oxide based film having a foam structure. The nano-porous silicon oxide based films are useful for filling gaps between metal lines with or without liner or cap layers. The nano-porous silicon oxide based films may also be used as an intermetal dielectric layer for fabricating dual damascene structures. Preferred nano-porous silicon oxide based films are produced by reaction of 1,3,5-trisilanacyclohexane, bis(formyloxysilano)methane, or bis(glyoxylylsilano)methane and hydrogen peroxide followed by a cure/anneal that includes a gradual increase in temperature.

An anode structure for lithium batteries includes nanofeatured silicon particulates dispersed in a conductive network. The particulates are preferably made from metallurgical grade silicon powder via HF/HNO₃ acid treatment, yielding crystallite sizes from about 1 to 20 nm and pore sizes from about 1 to 100 nm. Surfaces of the particles may be terminated with selected chemical species to further modify the anode performance characteristics. The conductive network is preferably a carbonaceous material or composite, but it may alternatively contain conductive ceramics such as TiN or B₄C. The anode structure may further contain a current collector of copper or nickel mesh or foil.

An Si/C composite includes carbon (C) dispersed in porous silicon (Si) particles. The Si/C composite may be used to form an anode active material to provide a lithium battery having a high capacity and excellent capacity retention.

A process for producing an adhered SOI substrate without causing cracking and peeling of a single-crystal silicon thin film. The process consists of selectively forming a porous silicon layer in a single-crystal semiconductor substrate, adding hydrogen into the single-crystal semiconductor substrate to form a hydrogen-added layer, adhering the single-crystal semiconductor substrate to a supporting substrate, separating the single-crystal semiconductor substrate at the hydrogen-added layer by thermal annealing, performing thermal annealing again to stabilize the adhering interface, and selectively removing the porous silicon layer to give single-crystal silicon layer divided into islands.

A porous silicon based material comprising porous crystalline elemental silicon formed by reducing silicon dioxide with a reducing metal in a heating process followed by acid etching is used to construct negative electrode used in lithium ion batteries. Gradual temperature heating ramp(s) with optional temperature steps can be used to perform the heating process. The porous silicon formed has a high surface area from about 10 m²/g to about 200 m²/g and is substantially free of carbon. The negative electrode formed can have a discharge specific capacity of at least 1800 mAh/g at rate of C/3 discharged from 1.5V to 0.005V against lithium with in some embodiments loading levels ranging from about 1.4 mg/cm² to about 3.5 mg/cm². In some embodiments, the porous silicon can be coated with a carbon coating or blended with carbon nanofibers or other conductive carbon material.

There are many inventions described and illustrated herein. In one aspect, the present invention is directed to a MEMS device, and technique of fabricating or manufacturing a MEMS device, having mechanical structures encapsulated in a chamber prior to final packaging. The material that encapsulates the mechanical structures, when deposited, includes one or more of the following attributes: low tensile stress, good step coverage, maintains its integrity when subjected to subsequent processing, does not significantly and/or adversely impact the performance characteristics of the mechanical structures in the chamber (if coated with the material during deposition), and/or facilitates integration with high-performance integrated circuits. In one embodiment, the material that encapsulates the mechanical structures is, for example, silicon (polycrystalline, amorphous or porous, whether doped or undoped), silicon carbide, silicon-germanium, germanium, or gallium-arsenide.

The invention provides a porous silicon carbon composite microsphere with a yolk-eggshell structure and a preparation method therefor, and belongs to the lithium ion battery electrode material technology field. The porous silicon carbon composite microsphere takes a porous submicron silicon sphere mpSi as a core with a diameter of 400-900 nm, and takes porous carbon mpC as a shell with a thickness of 10-60 nm. The inner diameter of a cavity Void is 800-1400 nm. The composition of the silicon carbon composite microsphere can be described as mpSi@Void@mpC. In addition, In the preparation method, cheap silicon dioxide is taken as a silicon source, silicon dioxide is conversed into silicon materials with electrochemical activities through a magnesiothermic reduction method. The size of gaps can be regulated and controlled through control of etching conditions. The preparation method is advantaged in that the material structure can be controlled, the cost is low, the process is simple, and the composite microsphere is convenient for large-scale production.

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.

Disclosed in the invention are a silicon-carbon composite anode material for lithium ion batteries and a preparation method thereof The material consists of a porous silicon substrate and a carbon coating layer. The preparation method of the material comprises preparing a porous silicon substrate and a carbon coating layer. The silicon-carbon composite anode material for lithium ion batteries has the advantages of high reversible capacity, good cycle performance and good rate performance. The material respectively shows reversible capacities of 1,556 mAh, 1,290 mAh, 877 mAh and 474 mAh/g at 0.2 C, 1 C, 4 C and 15 C rates; the specific capacity remains above 1,500 mAh after 40 cycles at the rate of 0.2 C and the reversible capacity retention rate is up to 90 percent.

An improved method for forming shallow trench isolation structures having reduced stress and allowing for greater control over shape, size and characteristics of the shallow trench isolation structures is disclosed. The isolation trench is defined by implanting a substrate through a patterned mask to create heavily doped regions. These heavily doped regions are anodized to form porous silicon and then oxidized. The oxidized porous silicon is removed, leaving behind a trench having rounded corners which is filled with an isolation dielectric.

The invention provides a method for preparing a porous silicon/carbon composite material by using diatomite as the raw material, which is characterized by comprising the following steps of: with the diatomite as the raw material, performing simple refinement and purification processing to obtain silicon with a porous structure by means of metallothermic reduction; performing mechanical ball-milling with the carbon materials and/or precursors of carbon, hydro-thermal carbonization, pyrolytic carbonization or chemical vapor deposition to prepare the porous silicon/carbon composite material. Thecomposite material can be directly used as the cathode of the lithium ion battery, or can be mixed with other cathode materials to be used as the cathode materials of the lithium ion battery. Compared with a pure silicon material as the cathode material of the lithium ion battery, the porous silicon/carbon composite material has the advantages that the first reversible capacity and the circulation stability of the material are greatly improved. In the method, the inexpensive and accessible natural minerals are used as the raw materials, thus the cost is low and the preparation method is simple.

A design and manufacturing method for a photovoltaic (PV) solar cell less than 100 μm thick are disclosed. A porous silicon layer is formed on a wafer substrate. Portions of the PV cell are then formed using diffusion, epitaxy and autodoping from the substrate. All front side processing of the solar cell (junctions, passivation layer, anti-reflective coating, contacts to the N⁺-type layer) is performed while the thin epitaxial layer is attached to the porous layer and substrate. The wafer is then clamped and exfoliated. The back side of the PV cell is completed from the region of the wafer near the exfoliation fracture layer, with subsequent removal of the porous layer, passivation, patterning of contacts, deposition of a conductive coating, and contacts to the P⁺-type layer. During manufacturing, the cell is always supported by either the bulk wafer or a wafer chuck, with no processing of bare thin PV cell

A method for treating a film of material, which can be defined on a substrate, e.g., silicon. The method includes providing a substrate comprising a cleaved surface, which had a porous silicon layer thereon. The substrate may have a distribution of hydrogen bearing particles defined from the cleaved surface to a region underlying said cleaved surface. The method also includes increasing a temperature of the cleaved surface to greater than about 1,000 Degrees Celsius while maintaining the cleaved surface in a etchant bearing environment to reduce a surface roughness value by about fifty percent and greater. Preferably, the value can be reduced by about eighty or ninety percent and greater, depending upon the embodiment.

The invention discloses a porous silicon/carbon composite material and a preparation method thereof, and belongs to the fields of electrochemistry and new energy materials. The method comprises the following steps of: preparing porous silicon dioxide by using ethyl orthosilicate, silicon tetrachloride, methyl silicone oil and sodium silicide as raw materials, reducing the porous silicon dioxide into porous silicon, coating the porous silicon by adopting an organic carbon source, and performing thermal treatment under an inert atmosphere to prepare the porous silicon/carbon composite material. The material can be directly used as the lithium ion battery cathode material, the first discharge specific capacity of the material can reach 1,245mAh/g, the specific capacity can also reach 1,230mAh/g after 30 cycles, and the material has excellent charge/discharge performance.

A metal-type catalyst for hydrosaturating arylhydrocarbon is composed of the carrier containing porous silicon oxide-aluminium oxide and the hydrogenating active components. Said porous silicon oxide-aluminium oxide has the crystal type chosen from gamma, etc, theta, delta and X ones of aluminium oxide. Its advantages are easy preparing, high resistance to sulfur, and high hydrogenating activity.

A semiconductor structure that includes a monocrystalline germanium-containing layer, preferably substantially pure germanium, a substrate, and a buried insulator layer separating the germanium-containing layer from the substrate. A porous layer, which may be porous silicon, is formed on a substrate and a germanium-containing layer is formed on the porous silicon layer. The porous layer may be converted to a layer of oxide, which provides the buried insulator layer. Alternatively, the germanium-containing layer may be transferred from the porous layer to an insulating layer on another substrate. After the transfer, the insulating layer is buried between the latter substrate and the germanium-containing layer.

A porous silicon implant (42; 60) impregnated with a beneficial substance, such as a micromineral required for healthy physiology, is implanted subcutaneously and is entirely corroded away over the following months/year to release the micromineral in a controlled manner. In a second embodiment the implant (62) may have a large number of holes (72) which contain beneficial substance and which are closed by bio-errodable doors (76, 78) of different thickness so as to stagger the release of the beneficial substance over time as the doors are breached.

A method and apparatus for slicing a semiconductor substrate. In one embodiment, the invention allows repetitive etching of a surface of the semiconductor substrate with a time dependent concentration of fluorine ions and a time dependent current I, such that multiple porous layers are obtained. The porous layer is released, and the released porous layer is removed from the surface of the substrate. The surface roughness of the porous layer is maintained within an acceptable or desired level of roughness value. The invention also provides an apparatus including a container having an etching solution. The semiconductor substrate may be protected by a tube covering at least a potion of said semiconductor substrate from said etching solution. The rate of insertion of said semiconductor substrate into the container is controlled to synchronize the lift-off with the insertion of the correct thickness of the semiconductor substrate. The anodising current is provided between two electrodes during operation.

The present invention is a MEMS-based two-phase LHP (loop heat pipe) and CPL (capillary pumped loop) using semiconductor grade silicon and microlithographic/anisotrophic etching techniques to achieve a planar configuration. The principal working material is silicon (and compatible borosilicate glass where necessary), particularly compatible with the cooling needs for electronic and computer chips and package cooling. The microloop heat pipes (μLHP™) utilize cutting edge microfabrication techniques. The device has no pump or moving parts, and is capable of moving heat at high power densities, using revolutionary coherent porous silicon (CPS) wicks. The CPS wicks minimize packaging thermal mismatch stress and improves strength-to-weight ratio. Also burst-through pressures can be controlled as the diameter of the coherent pores can be controlled on a sub-micron scale. The two phase planar operation provides extremely low specific thermal resistance (20-60W/cm²). The operation is dependent upon a unique micropatterened CPS wick which contains up to millions per square centimeter of stacked uniform micro-through-capillaries in semiconductor-grade silicon, which serve as the capillary “engine,” as opposed to the stochastic distribution of pores in the typical heat pipe wick. As with all heat pipes, cooling occurs by virtue of the extraction of heat by the latent heat of phase change of the operating fluid into vapor. In the cooling of a laptop computer processor the device could be attached to the processor during laptop assembly. Consistent with efforts to miniaturize electronics components, the current invention can be directly integrated with a unpackaged chip. For applications requiring larger cooling surface areas, the planar evaporators can be spread out in a matrix and integrally connected through properly sized manifold systems.

Embodiments of the invention provide a semiconductor device having dielectric material and its method of manufacture. A manufacturing method comprises forming a layer of silicon over a substrate, forming an opening through the layer of silicon, filling the opening with a conductor; and anodically etching the layer of silicon so as to form porous silicon. Embodiments may further include passivating the porous silicon such as by treating its surface with an organometallic compound. Other embodiments of the invention provide a semiconductor device comprising a layer comprising functional devices; and an interconnect structure over the layer, wherein the interconnect structure comprises a porous silicon dielectric. In an embodiment of the invention, the interconnect structure comprises a dual damascene interconnect structure. Other embodiments may include a passivation step after the step of oxidizing the porous silicon.

The invention relates to processes for the synthesis of 2-D and 3-D periodic porous silicon structures and composites with improved properties having the advantages of porous silicon and photonic bandgap materials. Photonic crystals comprise a two dimensionally periodic or three dimensionally periodic microporous structural matrix of interconnecting, crystallographically oriented, monodispersed members having voids between adjacent members, and said members additionally having randomly nanoporous surface porosity. The silicon nanofoam material shows enhanced and spectrally controlled/tunable photoluminescence and electroluminesce and finds use as transparent electrodes, high-lumonosity light emitting diodes (LEDs), wavelength division multiplexors, high-active-area catalyst supports, photonic bandgap lasers, silicon-based UV detectors, displays, gas sensors, and the like.

The present invention belongs to the field of porous ceramic material technology, and is the preparation process of one low cost and high performance porous silicon nitride/silicon carbide ceramic. The preparation process includes compounding material, forming and sintering as the conventional ceramic material preparing steps. It features that phenolic resin used as pore creating agent and carbon source is in-situ produced into SiC phase through the carbon hot reduction during sintering; and that Si3N4, Al2O3, Y2O3 and phenolic resin in certain proportion are produced into slurry through adding anhydrous alcohol and mixing for 12-24 hr and stoved into powder; and that the ceramic powder is processed through formation, cracking to eliminate glue, carbon hot reduction and sintering to produce the porous ceramic material with porosity of 40-70 %, strength of 70-160 MPa and low cost.

Embodiments of the present invention are directed to a substrate for performing ionization desorption on porous silicon, methods for performing such ionization desorption and methods of making substrates. One embodiment directed to a substrate for performing ionization desorption on silicon comprises a substrate having a surface having a formula of:

As used above, X is H or Y, where at least at least twenty five mole percent of X is Y and Y is hydroxyl, or —O—R₁, or O—SiR₁, R₂, R₃ wherein R₁, R₂, and R₃ are selected from the group consisting of alkyl, alkenyl, alkynyl, aromatic, amino alkyl, amino alkenyl, amino alkynyl, pyridinyl, pyrridonyl, and carbonyl, alcohol and carboxylic acid derivatives thereof having one to twenty five atoms, and hydroxyl, amino, amide, carboxyl, ester, carbonyl, sulfhydryl, sulfonyl, phosphoral, bromo, iodo, chloro and fluoro derivatives. The letter “n” represents an integer from 1 to infinity and any vacant valences are silicon atoms, hydrogen or impurities.