Abstract: A method for cleaving a semiconductor crystal body having a first surface and an opposite second surface, comprising the steps of forming a channel on the first surface of the semiconductor, scribing a portion of the second surface opposite the channel on the first surface, and mechanically cleaving the semiconductor along a plane defined by said channel on the first surface and said scribe on the second surface.

Abstract: A method of manufacturing a microminiature vacuum tube includes forming a mask layer on a first surface of a monocrystalline substrate and removing the mask layer where a cathode is to be formed, anisotropically etching the monocrystalline substrate at the surface using the mask layer to form a recess in the substrate having a V-shaped cross-section, covering the V-shaped recess with an electron-emitting cathode material, successively forming a first insulator film, a gate material, a second insulator film, and an anode material on the second surface of the substrate, removing portions of the anode material, second insulator film, gate material, and first insulator film from a portion of the second surface opposite the V-shaped recess, and etching the monocrystalline substrate using the first insulator film as a mask until the tip of the cathode material is exposed. Uniformly shaped cathodes can be formed with good controllability and reproducibility according to the invention.

Abstract: A process for producing a high-purity silica, which comprises the steps of reacting a crude silica with ammonium fluoride, acid ammonium fluoride or a mixture thereof in an aqueous medium to produce ammonium silicofluoride, separating the ammonium silicofluoride from an unreacted silica and impurities by the means of a solid/liquid separation, and reacting the thus-obtained ammonium silicofluoride with ammonia in an aqueous medium. This process is a low cost process, and enables to control properties of silica.

Abstract: Production of siliceous precipitates, for example sodium aluminosilicates by decomposition of an alkali metal sulfite solution with a solution of a sulfitic species such as sulfur dioxide, sulfurous acid or a salt thereof. Precipitates having excellent properties are obtained and the co-produced aqueous phase is a solution of alkali metal sulfite which has utility in pulp and paper mills. The process is advantageously carried out in proximity to a pulp and paper making operation wherein the siliceous precipitate may be used as a paper making filler and the alkali metal sulfite solution may be used in the pulping process.

Abstract: There is provided a composite oxide represented by the formulaiR.sub.2 O.jAl.sub.2 O.sub.3.kTiO.sub.2.mSiO.sub.2.nH.sub.2 Owherein R denotes an alkali metal, i is 0.3 to 1, k is 0 to 0.9, j+k=1, m is 7 to 70 and n is 0.2 to 0.4,said composite oxide being amorphous, and its cumulative specific pore volume of pores having a pore radius of 10.sup.4 A or less being 2.0 to 3.0 cc/g. This composite oxide can be produced by a process which comprises a first reaction step of adding an acid aqueous solution capable of forming a silicate by reaction with an alkali silicate to 7 to 10% by weight, calculated as silica, of an alkali silicate aqueous solution in the presence of a salt at 10.degree. to 45.degree. C. such that a neutralization ratio becomes 20 to 40%, and a second reaction step of heating the reaction solution obtained in the above reaction at a temperature of 90.degree. C.

Abstract: A wafer structure suitable for the formation of semiconductor devices thereon and having a buried interconnect structure for interconnection of desired ones of the semiconductor devices according to a predetermined interconnection pattern and a method of making the same is disclosed. The wafer structure comprises a primary substrate having a first thickness appropriate for the formation of the desired semiconductor devices.

Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of carbon from a source containing less than 0.2% by weight of iron, with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere in the presence of 0.2-10% by weight of an oxide or oxide precursor of Ca, Mg, Al, W, Ce or Cu; 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, and preferably 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less. The carbon is preferably in the form of particles of less than 50 .mu.m and the silica or precursor is preferably in the form of particles of less than about 45 .mu.m. The weight ratio of silica to carbon is greater than 1.76:1. The carbon source is preferably a pure form of carbon, e.g. graphite or amorphous carbon.

Abstract: A semiconductor device is disclosed which comprises a semiconductor substrate and an insulating film disposed on the substrate. The insulating film is a oxynitride film prepared by nitriding a thermal oxide film, which has been formed on the substrate, in an atmosphere of nitriding gas. The nitriding is conducted for a nitridation time of 10.sup.6.6-T N.sup./225 seconds or shorter wherein T.sub.N is in the nitridation temperature in degree centigrade, or conducted so as to have a nitrogen concentration of about 8 atomic % or less, at least in the vicinity of the interface between the oxynitride film and the substrate. Also disclosed is a method for the production of the semiconductor device.

Abstract: A method for processing chlorosilane distillation residues by hydrolysis with steam, in which the hydrolysis is carried out at escalating temperatures from about 130.degree. C. to at least 170.degree. C.

Abstract: A method of producing a composite ceramic powder is provided herein. A precursor product powder is first produced in a reactor from at least one carbide-forming reactant by heating the reactant(s) by means of combustion of a fuel, and the precursor product powder as collected from the reactor is heated in a nitrogen-containing atmosphere to produce a final product comprising a carbide compound as well as a nitride compound.

Abstract: A dynamic RAM comprises an array of memory cells, each of the memory cells comprising a single access transistor and a charge storage region. The charge storage region comprises a first capacitor memory including a P.sup.+ region serving as an opposite electrode formed in the inner surface of a trench formed in a P type silicon substrate, a first capacitor dielectric film formed on the P.sup.+ region and a common electrode layer serving as a memory terminal formed on the first capacitor dielectric film, and a second memory capacitor including the common electrode layer, a second capacitor dielectric film formed on the common electrode layer and a cell plate electrode formed on the second capacitor dielectric film. The memory terminal and a drain region of the access transistor are connected in a self-aligning manner by an electrode having a sidewall shape which is in contact with an end of the memory terminal.

Abstract: A method of forming a field emission device including the steps of selective deposition of a column/ridge within the confines of a conformally deposited insulator layer and subsequent directional deposition to form a cone/wedge, having a geometric discontinuity of small radius of curvature, on the column/ridge is provided.

Abstract: To prepare silicon nitride having a crystallite size of 40 to 60 nm and a specific surface area according to BET of 21 to 40 m.sup.2 /g, amorphous silicon nitride or amorphous silicon nitridoimide is brought into surface contact with gas containing water vapor or water-containing solvents and the amorphous silicon nitride or amorphous silicon nitridoimide thus surface-contacted is heated under a nitrogen atmosphere at a heating rate of at least 1.degree. C./minute to above the crystallization temperature of .alpha.-silicon nitride, which is above 1100.degree. C.

Abstract: A process for waste liquid-free processing of residues of chlorosilane distillations, wherein the residue is allowed to react with liquid hydrochloric acid accompanied by the release of hydrogen chloride, the resulting reaction mixture is allowed to coagulate, the solid phase is separated and dried and heat-treated, and the liquid phase and the condensed gaseous constituents are recycled into the process.

Abstract: The hydrogen content of polysilicon can be reduced by heat treatment. The process is preferably conducted on polysilicon particles in bead-like form produced by chemical vapor deposition in a fluidized bed. The heat treatment is preferably conducted at a temperature of 1020.degree.-1200.degree. C. for a time from about 6 hours to about 1 hour sufficient to reduce the hydrogen content, and insufficient to cause agglomeration of the particles being treated. In order to reduce the tendency of particles to agglomerate at the process temperature employed, the particle bed is preferably maintained in motion during the dehydrogenation. The products produced by the process can have a hydrogen content of 30 ppma or less. These improved products can be used to produce monocrystalline silicon for the production of semiconductor devices.

Abstract: A process for hydrofluoric acid digestion of inorganic silica/alumina matrix material for the production of silicon tetrafluoride and aluminum fluoride comprises the initial step of reacting the matrix material with hydrofluoric acid, to form silicon tetrafluoride gas and a solution/slurry containing aluminum fluoride, undigested oxides, and additional soluble and insoluble fluoride materials. The silicon tetrafluoride gas is purified of contaminants by condensing out impurities in cold traps and reacted with aqueous sodium fluoride to form a solution/slurry of fluorosilicate salt which is delivered to a filter press to separate sodium fluorosilicate powder from the solution/slurry. The sodium fluorosilicate powder is dried and delivered to a kiln at a temperature of about 600.degree. C. to 650.degree. C. to form substantially pure silicon tetrafluoride gas and sodium fluoride powder for collection.

Abstract: Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

Abstract: An SOI wafer is formed having a silicon-germanium layer between the epitaxial layer of the device and the insulative layer. The process includes bonding a second substrate to a silicon-germanium layer on a first substrate by an intermediate insulative layer. The first substrate is removed down to the silicon-germanium layer and the silicon layer is epitaxially formed on the silicon-germanium layer.

Abstract: A suitable inert gas such as argon or a mixture of inert and reactive gases such as argon and hydrogen is introduced onto the backside of wafers being processed in a CVD reactor during the deposition of tungsten or other metals, metal nitrides and silicides, to avoid deposition of material on the backside of the wafers being processed. Each process station includes a gas dispersion head disposed over a platen. A vacuum chuck including a number of radial and circular vacuum grooves in the top surface of the platen is provided for holding the wafer in place. A platen heater is provided under the platen. Backside gas is heated in and about the bottom of the platen, and introduced through a circular groove in the peripheral region outside of the outermost vacuum groove of the vacuum chuck. Backside gas pressure is maintained in this peripheral region at a level greater than the CVD chamber pressure.

Abstract: A process is disclosed for the hydrothermal production of potassium silicate solutions with high SiO.sub.2 :K.sub.2 O molar ratios, by the hydrothermal reaction of quartz sand with aqueous potassium hydroxide solutions at temperatures in the range of 150.degree. to 300.degree. C. at the pressures of saturated water vapor corresponding to these temperatures in a pressure reactor, which is characterized in that the potassium silicate solutions obtained thereby, which have SiO.sub.2 :K.sub.2 O molar ratios of less than 2.75:1, are then reacted with a quartz tempered at temperatures in the range of over 1100.degree. C. up to melting point, the temperatures and pressures also being maintained in the ranges named.