Abstract: The periodic stress and strain fields produced by a pure twist grain boundary between two single crystals bonded together in the form of a bicrystal are used to fabricate a two-dimensional surface topography with controllable, nanometer-scale feature spacings (e.g., from 50 nanometers down to 1.5 nanometers). The spacing of the features is controlled by the misorientation angle used during crystal bonding. One of the crystals is selected to be thin, on the order of 5-100 nanometers. A buried periodic array of screw dislocations is formed at the twist grain boundary. To bring the buried periodicity to the surface, the thin single crystal is etched to reveal an array of raised elements, such as pyramids, that have nanometer-scale dimensions. The process can be employed with numerous materials, such as gold, silicon and sapphire. In addition, the process can be used with different materials for each crystal such that a periodic array of misfit dislocations is formed at the interface between the two crystals.

Abstract: A method of producing a single crystal of the composition M3NbGa3Si2O14 (where M is an alkaline earth metal) comprising growing in a lattice direction inclined at an angle of 50.8 to 90 degrees from a [001] axis. The single crystal obtained in this way may be suitably used as a component of a resonator, filter, or other various piezoelectric elements.

Abstract: An epitaxial compound structure has a crystal structure including fluorite crystal on which is epitaxially grown a film of simple perovskite crystal with a (011) orientation.

Abstract: A Cerium-Doped Lutetium Oxyorthosilicate scintillator boule having a graded decay time. The method for manufacturing an LSO:Ce crystal boule having a decay time gradient decreasing from the top end to the bottom end first includes the step selecting an iridium crucible. The crucible is selected based upon its diameter relative to the diameter defined by said crystal boule. The crucible is also selected based upon its volume relative to the volume of the crystal boule to be grown. A Cerium dopant (CeO2) is added to a mixture of Lutetium Oxide (Lu2O3) and Silicon Dioxide (SiO2). The composition is heated until melted to define a melt. A seed crystal is then placed in contact with the melt, is rotated, and slowly withdrawn, thereby yielding an LSO:Ce crystal boule defining a decay time gradient.

Abstract: A cylindrical alkali halide melt-grown single-crystal-type ingot is axially compressed in a heated dual-platen press while in a plastic state. The ingot is located mid-way between two parallel, planar, vertically extending barriers. By properly orienting the platens and the barriers with respect to the crystal lattice structure of the ingot, the ingot can be forged into a rectangular block that is not only devoid of peripheral cracks and fissures but that also has more uniform properties even when impurities and activator (Tl, in the case of NaI(Tl)) are not uniformly distributed within the initial single-crystal ingot.

Abstract: In single crystal SiC according to the present invention, a single crystal &agr;-SiC substrate and a polycrystalline &bgr;-SiC plate are laminated to each other for fixation, the single crystal &agr;-Sic substrate and the polycrystalline &bgr;-SiC plate are subjected to heat treatment under an inert gas atmosphere and a saturated SiC vapor atmosphere, whereby the single crystallization owing to solid-phase transformation of the polycrystalline &bgr;-SiC plate and a progress of the single crystallization to a surface direction wherein a contact point is regarded as a starting point make a whole surface of layer of the polycrystalline &bgr;-SiC plate grow efficiently into a single crystal integrated with the single crystal &agr;-SiC substrate, whereby it is possible to produce single crystal SiC having high quality with high productivity, which is substantially free from lattice defects and micropipe defects.

Abstract: New methods for growing threading dislocation free heteroepitaxy are proposed and investigated theoretically. The first method contains four key steps: Stranski-Krastanov island formation, strain relaxation by defect nucleation, in-situ defect removal, and island coalescence. The central idea is that the defects are utilized to relax the lattice strain, and as soon as the strain is relaxed, the dislocation segments are removed that will propagate to the surface of the film. As a result, the heteroepitaxial film is expected to be relaxed but be free of harmful threading dislocations regardless of the degree of lattice mismatch. In the second method, single crystal islands or patches are grown initially which are a few hundred nanometers or less in diameter. The patches serve as nucleation sites for growth of single crystal heteroepitaxial layers. Because of the very small patch size, the stress (normal stress and shear stress) due to lattice mismatch will be reduced significantly.

Abstract: A complex (M) which is formed by growing a polycrystalline .beta.-SiC plate 4 by the thermal CVD method on crystal orientation faces which are unified in one direction of plural plate-like single crystal .alpha.-SiC pieces 2 that are stacked and closely contacted is subjected to a heat treatment at a temperature in the range of 1,850 to 2,400.degree. C., whereby a single crystal which is oriented in the same direction as the crystal axes of the single crystal .alpha.-SiC pieces 2 is grown from the crystal orientation faces of the single crystal .alpha.-SiC pieces toward the polycrystalline .beta.-SiC plate 4. As a result, single crystal SiC of a high quality in which crystalline nuclei, impurities, micropipe defects, and the like are not substantially generated in an interface can be produced easily and efficiently.

Abstract: There is disclosed a method for heat treatment of a silicon substrate produced by the CZ method by utilizing a rapid thermal annealer, wherein the heat treatment is performed under an atmosphere composed of 100% nitrogen, or 100% oxygen, or a mixed atmosphere of oxygen and nitrogen by heating the silicon substrate to a maximum holding temperature within a range of from 1125.degree. C. to the melting point of silicon, and holding the substrate at that maximum holding temperature for a holding time of 5 seconds or more, and then the substrate is rapidly cooled at a cooling rate of 8.degree. C./second or more from the maximum holding temperature. In the method, the amount of oxygen precipitation nuclei in the substrate can be controlled by changing the maximum holding temperature and the holding time.

Abstract: An LiGaO.sub.2 single crystal manufactured by the Czochralski method has a crystallographic axis as a pulling direction set within an angle range of 30.degree. from a b- or a-axis direction. An LiGaO.sub.2 single-crystal substrate and a method of manufacturing the single crystal and the substrate are also disclosed.

Abstract: A method and apparatus for creating unique gemstones is provided. The method comprises the steps of optically contacting the gemstones of interest followed by a heat treatment of the composite gemstone. The heat treatment step increases the bond strength and therefore the resistance of the bond to reversal. In one aspect of the invention, a composite gem is fabricated by bonding a naturally occurring gem to an artificial gem to form a single composite gemstone of large size that outwardly appears to be a single natural gem. The composite gem may be fabricated at a fraction of the cost of a natural stone of the same size. In another aspect of the invention, an intensely colored natural stone is bonded to a colorless or lightly colored artificial stone. This composite retains the intense color associated with the natural stone while enjoying the brilliance, depth, and size resulting from the combination of stones.

Abstract: A surface treating method of single crystals by which single crystals for substrates having finished surfaces showing pit-free and atomic scale step structures are obtained by treating the {100}-plane surfaces of single-crystal SrTiO.sub.3 substrates by dissolving two-dimensional-lattice atomic layers forming the surfaces one layer by one layer by using a fluorine-based acidic solution (maintained at >35.degree. C. in temperature and <4 in pH) as a solution A and water as a solution B by alternately immersing the substrates in the substrates in the solution A and B.

Abstract: A method of forming defect-free permanent bonds without the use of adhesives as well as devices formed by this method is disclosed. In general, the disclosed process allows similar or dissimilar crystalline, vitreous or dense polycrystalline ceramic, metallic or organic polymeric components to be first joined by optical contacting and then heat treated to stabilize the bond. The heat treatment can be performed at a low enough temperature to prevent interdiffusion between species, thus insuring that the bond is not subjected to excessive mechanical stresses and that the materials do not undergo phase changes.

Abstract: The invention relates to the growth of nickel manganese oxide monocrystals having a cubic spinel geometry. Methods of their growth and sensors constructed with same are also described.

Abstract: A cylindrical alkali halide single-crystal-type ingot having an axis generally coinciding with the ?001! crystallographic direction is compressed in a heated dual platen press. To produce an approximately rectangular compressed ingot that is devoid of cracks and fissures at and adjacent the periphery, the surface of the ingot is flatted. For crystals having a face-centered lattice (e.g. NaI), the flat is parallel to the (100) crystallographic plane. For crystals having a body-centered lattice (e.g. CsI), the flat is parallel to the (110) crystallographic plane. The flat is placed on the lower platen of the press to properly orient the crystallographic structure of the ingot with respect to the direction of compression.

Abstract: A silicon semiconductor wafer is constructed from three mutually inclined monocrystalline regions (6, 7, 8) which form three circular sectors of the wafer whose interfaces and boundary lines consequently extend radially with respect to one another and form angles (W6, W7, W8) of less than 180.degree. with one another. In this arrangement, two of the interfaces are first-order twin grain boundaries between two <111> crystal planes in each case. The silicon semiconductor wafer is used to produce inexpensive high-performance solar cells.

Abstract: The invention concerns materials which exhibit photonic band gaps in the near infrared and visible regions of the optical spectrum and methods of preparation of such materials.

Abstract: A method of making a single crystal Ga*N article, including the steps of: providing a substrate of crystalline material having a surface which is epitaxially compatible with Ga*N; depositing a layer of single crystal Ga*N over the surface of the substrate; and etchably removing the substrate from the layer of single crystal Ga*N, to yield the layer of single crystal Ga*N as said single crystal Ga*N article. The invention in an article aspect relates to bulk single crystal Ga*N articles, such as are suitable for use as a substrate for the fabrication of microelectronic structures thereon, and to microelectronic devices comprising bulk single crystal Ga*N substrates, and their precursor structures.

Abstract: A modified process for synthesizing diamond having developed by further improving a process of diamond synthesis based on combustion method, which provides diamond grains 1.5 mm or larger in crystal diameter at good economy. The process comprises burying one or two or more seed crystal diamond grain(s) 2 into the surface of a substrate 1, and striking a combustion flame on said seed crystal diamond grain(s) 2 while cooling the substrate 1 to thereby allow diamond to grow on the seed crystal diamond 2 into a larger diamond grain.

Abstract: In order to stably retain an oxide-based melt consisting essentially of yttrium or a lanthanoid element, barium, copper and oxygen at a prescribed temperature with no impurity contamination thereby preparing a large oxide crystal of high quality from the melt, an oxide melt consisting essentially of yttrium or a lanthanoid element, barium, copper and oxygen is stored in a first crucible, which in turn is held in a second crucible. The first crucible is made of a material which is an oxide of at least one element forming the melt having a melting point higher by at least 10.degree. C. than a melt retention temperature and causing no structural phase transition up to a temperature higher by 10.degree. C. than the aforementioned prescribed temperature, with solubility of not more than 5 atomic percent with respect to the melt in a temperature range from the room temperature to a temperature higher by 10.degree. C. than the melt retention temperature.

Abstract: A method of fabricating bulk superconducting material including RBa.sub.2 Cu.sub.3 O.sub.7-.delta. comprising heating compressed powder oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa.sub.2 Cu.sub.3 O.sub.7-.delta. in physical contact with an oxide single crystal seed to a temperature sufficient to form a liquid phase in the RBa.sub.2 Cu.sub.3 O.sub.7-.delta. while maintaining the single crystal seed solid to grow the superconducting material and thereafter cooling to provide a material including RBa.sub.2 Cu.sub.3 O.sub.7-.delta.. R is a rare earth or Y or La and the single crystal seed has a lattice mismatch with RBa.sub.2 Cu.sub.3 O.sub.7-.delta. of less than about 2% at the growth temperature. The starting material may be such that the final product contains a minor amount of R.sub.2 BaCuO.sub.5.

Abstract: This invention discloses a method of synthesizing a Group III-V compound semi-conducting film from a Group III metal alkyl and Group V hydride wherein the method comprises providing a vacuum chamber in which the synthesis takes place, adsorbing at least one monolayer of said Group III metal alkyl on an inert surface, backfilling the chamber with a Group V hydride, adsorbing the Group V hydride on the inert surface, providing atomic hydrogen atoms from electron-induced dissociation of Group V hydride adsorbed on the surface, inducing an electron-induced depletion of carbon at a rate which is dependent on the pressure of the Groups V hydride, retaining substantially all Group III metal on the surface and providing a thermally stable Group III-V compound semi-conducting film on the inert SiO.sub.2 surface. Methods for synthesizing a multilayer Group III-V semi-conducting film and specifically a GaN film are also disclosed, along with the apparatus for the synthesis of Group III-V compound semi-conducting films.

Abstract: A semiconductor device produced by forming an epitaxial layer insulated from a silicon substrate, and forming a device in the epitaxial layer. According to the process a silicon dioxide layer is formed on a semiconductor substrate. Then the silicon dioxide layer is provided with openings therein. Silicon is made to grow until it protrudes from the openings to thereby form a silicon seed crystal layer. Next, a silicon nitride layer is formed on the surface of the silicon seed crystal and thereafter is oxidized. A field oxide layer is thereby bonded at the lower portion of the openings so that the silicon seed crystal layer is insulated from the silicon substrate. Thereafter, epitaxial growth is effected from the silicon seed crystal layer. The growth is stopped just before silicon growth layers connect to one another, thus obtaining epitaxial grown layer having regions which are separated from one another. The device is formed in the epitaxially grown layer.

Abstract: When producing a single-crystal bulk ZnSe from a melt by a high-pressure melt technique in a vertical Bridgman (VB) furnace or a vertical gradient freezing (VGF) furnace, preliminarily grown polycrystalline ZnSe (which may be a crystal solely composed of twins) is used as a seed and, after melting the starting ZnSe material and part of the seed, a twin-free ZnSe bulk crystal is grown on the seed; alternatively, polycrystalline ZnSe is grown at the tip of the growing crystal and part of it is melted, followed by growing a single crystal on that polycrystal to produce a twin-free, high-purity ZnSe bulk crystal. In either way, the process assures that twin-free single crystals of bulk ZnSe can be produced with good reproducibility without adding dopants or using any materials that are difficult to obtain.

Abstract: A solid state seed crystal process for bulk conversion of a polycrystalline ceramic body to a single crystal body (of the same chemical composition) having the same crystal orientation as the seed crystal. The process comprises heating said body to form a monolithic join between the body and the seed crystal, heating the joined structure to reduce grain growth inhibitors and further heating the joined structure above the minimum temperature required for crystallite growth of the crystalline material, but not hot enough to melt and distort the original shape of the polycrystalline ceramic body during its conversion to a single crystal. This process has been used to convert polycrystalline alumina (PCA) bodies to sapphire having the same crystal orientation as the seed crystal by heating the PCA body, monolithically joined to a sapphire seed crystal, at a temperature above 1700.degree. C. without melting the body.

Abstract: A method for producing a photo-voltaic infrared detector including growing a crystalline CdHgTe layer on a CdTe substrate by liquid phase epitaxy using a growth melt including tellurium as a solvent to which indium is added as a dopant impurity in a concentration of from 0.01 to 0.1 ppm; annealing the CdHgTe layer to produce a p-type CdHgTe layer including indium as an n-type background dopant impurity; forming an n-type region of a desired depth as a light receiving region at the surface of the p-type CdHgTe layer by implanting a dopant impurity producing n-type conductivity and annealing; and forming an n-side electrode on the n-type region and a p-side electrode a prescribed distance from the n-type region on the p-type CdHgTe layer.

Abstract: In a method of selectively growing an Si epitaxial film, a gas consisting of not less than one type of a gas containing at least silane gas is used as a source gas. A substrate obtained by partially forming an insulating film pattern on a single-crystal Si substrate is heated to a predetermined temperature in a vacuum. An Si epitaxial film is grown on exposed single-crystal Si except for the insulating film pattern. Intermittent irradiation by vacuum ultraviolet light on the heated substrate is performed at predetermined time intervals.

Abstract: A solid state method of converting a polycrystalline ceramic body to a single crystal body includes the steps of doping the polycrystalline ceramic material with a conversion-enhancing dopant and then heating the polycrystalline body at a selected temperature for a selected time sufficient to convert the polycrystalline body to a single crystal. The selected temperature is less than the melting temperature of the polycrystalline material and greater than about one-half the melting temperature of the material. In the conversion of polycrystalline alumina to single crystal alumina (sapphire), examples of conversion-enhancing dopants include cations having a +3 valence, such as chromium, gallium, and titanium.

Abstract: Aluminium borate whiskers by which a composite material having a higher strength than ever is available by definitely suppressing a generation of spinel along the surface of the whiskers are prepared by heating aluminium borate whiskers bearing a r-alumina surface layer in an atmosphere of ammonia gas or ammonia gas and a hydrocarbon gas such that a layer of a nitro-oxide and oxide of aluminium is generated along the surface of the whiskers.

Abstract: A seed crystal is connected with a polycrystal at one end of the polycrystal, the connected crystal material is melted under a zero-gravity or microgravity environment without any container, and a single crystal is grown.

Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.

Abstract: A invention provides a method for production of diamond particles. The solvent metallic disk of a starting material specimen used in this diamond synthesis is divided into two layers. An intermediate layer is interposed between the two solvent metallic layers, so that the diamond crystals, formed on the two solvent metallic surfaces in contact with graphite disks and influenced by gravity, are not floated on the upper surface of the solvent metallic disk but grown at their positions in the individual solvent metallic layers at which they were nucleated. Hence, the method of this invention results in formation of the same number of diamond products, having the same size and desired good quality, on opposed surfaces or the upper and lower surfaces of the solvent metallic disk. The intermediate layer is a thin disk made of tungsten or molybdenum and having a thickness ranged from 10 .mu.m to 100 .mu.m.

Abstract: A method is disclosed for producing continuous CVD diamond films with at least two controlled diamond thermal conductivity layers having improved thermal conductivity in the direction parallel to the diamond film plane to increasing the lateral heat spreading ability of the diamond film. Also, disclosed is a method to decrease the time to deposit high thermal conducting diamond by chemical vapor deposition.

Abstract: A method for producing a surface-emitting laser, includes the steps of: forming a mask pattern to define a top mirror on a semiconductor substrate, the semiconductor substrate having a first semiconductor multilayer formed on the semiconductor substrate, a second semiconductor multilayer formed on the first semiconductor multilayer, and a third semiconductor multilayer formed on the second semiconductor multilayer, the first semiconductor multilayer constituting a bottom mirror, the second semiconductor layer including an upper barrier layer and a lower barrier layer, and an active layer sandwiched between the upper and lower barrier layers, the third semiconductor multilayer constituting a top mirror; forming the top mirror by partially removing the third semiconductor layer by dry etching using the mask pattern as a mask until the surface of the upper barrier layer of the second semiconductor multilayer is exposed; forming an etching protective film at least on the side of the top mirror; partially removing

Abstract: The invention concerns materials which exhibit photonic band gaps in the near infrared and visible regions of the optical spectrum and methods of preparation of such materials.The materials manufactured according to the invention are particularly suitable for use in the optical analog to semiconductor behavior, in which a photonic band gap material, or a plurality of such materials acting in concert, can be made to interact with and control light wave propagation in a manner analogous to the way that semiconductor materials can be made to interact with and control the flow of electrically charged particles, i.e., electricity, in both analog and digital applications.

Abstract: The present invention relates to a process for increasing the dimensions of quartz crystals and of quartz-isomorphic materials, which can be produced by hydrothermal growth from seed, in which a seed obtained by assembly of several crystalline plates is used, wherein there are assembled at least two plates of strictly identical lengths and/or widths and of similar thicknesses, cut in at least one crystal and having, on at least three faces crystalline orientations, the deviations from which remain, between the plates, smaller than about 10" of arc, and wherein said plates are brought together on a support by guidance elements, thus ensuring their alignment on the aforementioned three faces while maintaining crystalline orientation deviations smaller than about 10" of arc, one face per plate being left free for growth of the assembled seeds, leading to the production of a single crystal exhibiting at least one dimension greater than that corresponding to the original crystalline plate.