Abstract: A passivation layer of dielectric material disposed on the top surface of the SAW device prevents the metallized transducer pattern on the piezoelectric substrate from being exposed to chemical attack. This layer also provides for improved metal acousto-migration resistance through the well-known mechanism of grain boundary pinning. The piezoelectric SAW device substrate includes a dielectric layer which is disposed along the surface over the transducer metallization. The piezoelectric substrate includes metallized regions on top of the dielectric layer which is disposed over the substrate surface and the SAW transducers thereon. These metallized regions form capacitors to the transducer busses and capacitively couple electrical input and output signals to the transducers from external electronic apparatus.

Abstract: This is a new method for pulling a silicon single crystal. When the silicon single crystal is pulled from a quartz crucible which is provided with a rotation rate more than zero, exclusive of zero rpm according to the Czochralski process, a reference rotation rate of the quartz crucible is controlled by a predetermined program. This method is characterized in that a pulse-like increase or decrease in a rotation rate is superimposed to the reference rotation rate and differences in and cycles of the rotation rate are set by the predetermined program.

Abstract: A process for depositing a thin semiconductor film includes the steps of depositing a thin film on a substrate by feeding onto the surface of the substrate being heated a gaseous starting material containing a constituent element of the thin film, and feeding excited hydrogen to the thin film without exposing the thin film to the ambient air. Disilane was fed together with hydrogen carrier gas onto a quartz substrate to deposit thereon a thin amorphous silicon film, to which excited hydrogen from a hydrogen plasma was then fed to modify the deposited thin silicon film. As a result, the photoconductivity of the thin silicon film was improved.

Abstract: The invention relates to a method for the preparation of electronic and electro-optical components and circuits based on conducting polymers. One or more boundary surfaces in the component between a conducting polymer and another material are formed by melting of the conducting polymer.

Abstract: In a process for global planarizing of surfaces for integrated semiconductor circuits a locally planarized insulation layer of silicon oxide with one thickness is initially applied on a structured layer to be planarized having another thickness. Photoresist structures are generated thereon as an auxiliary plane inversely to the structured plane lying below. A further well-adhering and planarizing auxiliary layer, preferably formed of spin-on glass, is applied. It must be selected as a function of a following anisotropic back-etching, in such a way that its etching rate is greater than that of the photoresist layer and nearly the same as that of the silicon oxide layer. The photoresist structures remaining after the back etching are removed. A further insulating layer formed of silicon oxide is applied up to the selected insulator thickness.

Abstract: The present invention provides a method of removing impurities from a stream of silane, SiH.sub.4. Most notably, the present invention provides a method of removing ethylene from a silane stream by converting the ethylene to ethylsilane in the presence of a molecular sieve and distilling the desired silane from the ethylsilane contaminant.

Abstract: A method of forming a planarized or smoothed dielectric or other material layer upon a partially fabricated integrated circuit is disclosed. Conventional planarization techniques involve deposition of a dielectric or other material layer followed by anisotropic etchback. Unfortunately, some commercial equipment tends to etch the center of the wafer faster than the edges. The disclosed process forms a layer which is thicker in the central region than the edge region. Thus, when the disclosed process is followed by a conventional etchback, a planar dielectric or other material layer over the entire wafer is formed. Other aspects of the invention include processes and apparatus for producing smooth deposition and etching by control of the impedance of the etching and/or chemical precursor gases.

Abstract: A method of removing impurities from low grade silicon is provided comprising adding a zirconium compound to the low grade silicon for adsorbing the impurities.

Abstract: A method for patterning a metal layer without so-called "rabbit ears" comprising the steps of:deposition of a metal layer on a substrate, deposition of a barrier layer on the metal layer, formation of a mask layer of a predetermined pattern on the barrier layer, etching of the barrier layer and the metal layer under conditions such that the mask layer is also eroded slightly, and removal of the mask layer. In other embodiments, selective etching of barrier layer and mask sidewalls avoids or eliminates such "rabbit ears" and/or etchant product deposits which are precursors of such "rabbit ears".

Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

Abstract: A method of obtaining precipitated amorphous silicas with substantially a tertiary aggregate structure (whether as an aqueous slurry, as cake, gel or otherwise) useful for coating and/or incorporation in paper and other substrates (e.g. rubber, plastics and the like) from a geothermal fluid (naturally or artificially generated--natural, including water infusion into geothermal systems) having sufficient silicic acid concentration, said method comprising:A. ageing the fluid to effect polymerization, thus establishing a silica sol, ageing meaning a process in which the source fluid after being made supersaturated with respect to amorphous silica is held for a period of time,B. optionally (prior to, with and/or after step A--preferably prior to in order to reduce arsenic adsorption) reducing the temperature of the geothermal fluid and/or sol as the case may be,C. inducing precipitation of amorphous silica from the sol under conditions that will provide the tertiary aggregate structure, andD.

Abstract: A sol of flat silica particles (100-1000 nm in size) is produced by the following steps (a) to (d) from an acidic aqueous sol (S.sub.0) of negatively charged silica particles (7-30 nm in diameter) and an aqueous solution (B) of basic aluminum or zirconium salt.(a) mixing 100 parts by weight (as SiO.sub.2) of the sol (S.sub.0) with 0.2-10 parts by weight (as Al.sub.2 O.sub.3 or ZrO.sub.2) of the aqueous solution (B), and adjusting the resulting sol to pH 4-7, thereby yielding a sol (S.sub.1),(b) mixing 100 parts by weight (as SiO.sub.2) of the sol (S.sub.1) with 20-200 parts by weight (as SiO.sub.2) of the sol (S.sub.0), and adjusting the resulting sol to pH 4-7, thereby yielding a sol (S.sub.2),(c) mixing 100 parts by weight (as SiO.sub.2) of the sol (S.sub.2) with the aqueous solution (B) in an amount corresponding to 2-50% of the amount (as Al.sub.2 O.sub.3 or ZrO.sub.2 in parts by weight) added to 100 parts by weight (as SiO.sub.2) of the sol (S.sub.

Abstract: A process for preparing silicon carbide by carbothermal reduction which includes transporting, in a gaseous medium, a particulate reactive mixture of a silica source and a carbon source through a reaction zone. The heating rate of the atmosphere within the reaction zone is such that substantially all of the reactive mixture is heated at a heating rate of at least about 100.degree. C./second until an elevated temperature of at least 1800.degree. C. is reached. Either (1) carbon monoxide is added to the reaction zone or (2) a carbon monoxide level in the reaction is achieved in order to provide at least about 30 mole percent of the gases exiting the reaction zone to achieve a higher yield of silicon carbide.

Abstract: The silicon substrate in which mesa semiconductor elements are formed is scribed along dicing lines by a laser. The resolidified silicon, which failed to vaporize during scribing, is etched away by sodium hydroxide solution. As a result, the silicon substrate is separated into a plurality of mesa semiconductor pellets. These pellets undergo chemical etching with a fluoric and nitric acid mixture to smooth the cut surfaces.

Abstract: To prepare crystalline sodium silicates having a layer structure and the formula Na.sub.2 Si.sub.x O.sub.2x+1, in which x is between 2 and 3, sand and soda are first fused in a molar ratio of SiO.sub.2 /Na.sub.2 O of 2 to 3.5 at temperature of 1200.degree. to 1400.degree. C. The water-glass obtained in pieces after the melt has cooled is ground to particle sizes of less than 2 mm before it is treated at temperatures of 600.degree. to 800.degree. C. for 10 to 120 minutes in an elongated reaction zone with mechanical circulation. Finally, the material leaving the reaction zone is ground to a particle fineness of less than 1 mm.

Abstract: A process of forming an interconnection layer of polysilicon in a contact hole formed in an interlayer insulating film comprises opening the contact hole, depositing doped and nondoped polysilicon films in sequence, and etching back the polysilicon films by the reactive ion etching technique with at least one carbon fluoride gas to obtain the interconnection layer buried in the contact hole.

Abstract: Disclosed herein are a method and apparatus for purifying silicon, which are suitable for economical and mass production of high-purity silicon for solar cells from regular-grade silicon containing boron and carbon in large quantities. The method comprises directing a plasma jet stream of an inert gas toward the surface of molten silicon held in a container lined with silica or a silica-based refractory. For improved purification, the inert gas as the plasma gas is mixed with 0.1-10 vol % steam and/or less than 1 g of silica powder per liter of the inert gas at normal state. Alternatively, the container may have a bottom opening and is provided with an electrode having a cooling means underneath the bottom of the container, with the electrode and the cathode of the plasma torch connected to a power source for plasma generation, so that the plasma jet and electron beam are directed toward the surface of molten silicon.

Abstract: A method and apparatus are provided for producing a product comprising a nitride compound, such as for example silicon nitride. A reactor is provided which has a chamber defined therein which is divided into a combustion zone and a reaction zone. A combustible mixture is injected into the combustion zone and accordingly combusted to form hot combustion products. At least one reactant (i.e. silane) is injected at the boundary between the zones so as to be carried into the reaction zone by the combustion products and react to form raw product comprising the nitride compound. The raw product can be purified by subsequent processing to remove oxygen and convert by-products to the desired nitride compound. The product of the invention has a low level of impurities and is made up of primarily submicron, highly uniform particles. This makes the product particularly useful for fabrication of sintered ceramic parts.

Abstract: The present invention is a process for the production of silanes from the contact of silicon metal or a silicon containing material with hydrogen chloride. The described process employs a metal or metal compound on a solid support as a catalyst which increases the production of tetrachlorosilane. The metal or metal compound is selected from a group consisting of palladium and palladium compounds, rhodium and rhodium compounds, platinum and platinum compounds, iridium and iridium compounds, tin and tin compounds, nickel and nickel compounds, and aluminum and aluminum compounds. The process is run at a temperature of about 250.degree. C. to 500.degree. C.

Abstract: The present invention is a process for the carbothermic reduction of silicon dioxide to form elemental silicon. Carbon balance of the process is assessed by measuring the amount of carbon monoxide evolved in offgas exiting the furnace. A ratio of the amount of carbon monoxide evolved and the amount of silicon dioxide added to the furnace is determined. Based on this ratio, the carbon balance of the furnace can be determined and carbon feed can be adjusted to maintain the furnace in carbon balance.