Abstract: An epitaxial wafer for a light-emitting diode includes an n-type GaP single-crystal substrate, and at least an n-type semiconductor epitaxial layer and a p-type semiconductor epitaxial layer formed on the substrate. The substrate has a boron concentration of not more than 1.times.10.sup.17 cm.sup.-3. A light-emitting diode is fabricated using the epitaxial wafer thus formed provided with electrodes.

Abstract: Optoelectric article includes a substrate made of an optoelectric single crystal and a film of a single crystal of lithium niobate formed on the substrate by a liquid phase epitaxial process, wherein a ratio of lithium/niobium of a composition of the film of the lithium niobate single crystal falls in a range of 48.6/51.4 to 49.5 to 50.5 or 50.5/49.5 to 52.3/47.7.

Abstract: A Czochralski crystal growing system includes components for adding dopants to semiconductor materials and for growing single crystals. The components comprise a portion formed of a material that is chemically compatible with the semiconductor material. The portion includes a cavity sized to contain a desired amount of dopant. The cavity protects the dopant from exposure to contaminants, gas flows and heat in crystal growing furnaces. The portion is dipped into a melt to release the dopant. The portion can be a seed crystal which can further be used to grow a single crystal from the melt after doping. The components can include separate first and second portions formed of materials that are chemically compatible with the melt so that the portions can be placed into the melt. At least one of the first and second portions can contain a dopant. The second portion can be a seed crystal for growing a single crystal.

Abstract: A working recipe for NTD CZ and MCZ silicon wafer production is provided. It teaches that a neutron-enhanced S-curve can be constructed by noting that a silicon interstitial (Si.sub.I), emitted due to volume change during the traditional oxygen precipitation, can join a neutron-created vacancy in facilitating further oxygen loss via precipitation. The former relation is: 2Si+2O.sub.I .fwdarw.SiO.sub.2 +Si.sub.i the latter is: vacancy+Si .sub.I +2O.sub.I .fwdarw.SiO ..sub.2 The total loss of oxygen interstitials is:?O.sub.I !=Max(?O .sub.I !.sub.0 ?O .sub.I !.sub.s +min{2(?Si .sub.I !.sub.s +?Si .sub.I !.sub.0). ?vacancy!}),with subscripts 0 and s standing for initial state and S-curve prediction, respectively; ?Si.sub.I !.sub.s equal to 0.5?O .sub.I !.sub.s, and ?vacancy! readily obtainable by computer simulation. ?vacancy! is a function of the cadmium ratio (CR), silicon sample thickness, and total neutron fluence. The final oxygen interstitial content is: ?0.sub.I !.sub.f =max{?O.sub.I !.sub.0 -?O.sub.

Abstract: A process for oxidizing iron ions contained within iron-doped lithium niobate. The process comprises the steps of protonating the iron-doped lithium niobate crystal and then placing the same into a pressure chamber where between 10-100 atmospheres of dry, ultra-pure pressurized oxygen are applied. While under pressure, the crystal is heated to approximately 950.degree. C. at a rate not to exceed 50.degree. C. per minute, and preferably at a rate not less than 25.degree. C. per minute. The crystals are then continuously heated at approximately 950.degree. C. for approximately 50 hours and then cooled to 30.degree. C. at a rate not to exceed 50.degree. C. per minute, and preferably at a rate not less than approximately 25.degree. C. per minute. The resulting lithium niobate crystal will thereafter contain iron ions wherein the divalent iron ion ration to the trivalent iron ion ratio is approximately 1:100.

Abstract: A process and an apparatus for producing a polycrystalline semiconductor including charging a raw semiconductor material into a crucible, heating to melt the raw semiconductor material in the crucible by heating means, solidifying the melted material while depriving the bottom of the crucible of heat, and then cooling the crucible to cool the solidified semiconductor, in an atmosphere inert to the semiconductor throughout, characterized by alternately subjecting the semiconductor crystal to growth and annealing in the solidification step while periodically varying the amount of heat liberated from the raw semiconductor material.

Abstract: A method of growing a single crystal of semiconductor using a CZ growth technique, having a step (0<t<t1) wherein a single crystal of semiconductor is pulled while a source material is supplied continuously to maintain a constant amount of semiconductor melt, and a step (t2<t<t3) wherein the supply of source material is halted, and the single crystal of semiconductor is pulled using residual melt from the first step.

Abstract: Synthetic gemstones having extraordinary brilliance and hardness are formed from large single crystals of relatively low impurity, translucent silicon carbide of a single polytype that are grown in a furnace sublimation system. The crystals are cut into rough gemstones that are thereafter fashioned into finished gemstones. A wide range of colors and shades is available by selective doping of the crystal during growth. A colorless gemstone is produced by growing the crystal undoped in a system substantially free of unwanted impurity atoms.

Abstract: A method of growing a rare earth silicate single crystal from a melt of a starting material containing a rare earth oxide and a silicon oxide, wherein the starting material in which a density of Fe as an impurity is not more 0.1 ppm, a density of Al as an impurity is not more than 0.4 ppm, or the starting material showing a weight loss of not more than 1.0% when heated up to 1,000.degree. C. is used.This method which makes it possible to stably obtain a rare earth silicate single crystal having a good scintillator performance, such as free of voids and/or non-colored crystals, or may cause no poor fluorescent characteristics due to a compositional deviation of materials.

Abstract: A compound semiconductor crystal has a reduced dislocation density. The compound semiconductor crystal doped with an impurity satisfies the following relations, wherein c.c. represents its carrier concentration and .eta. represents its activation factor:.eta..ltoreq.c.c./(7.8.times.10.sup.15) (1).eta..ltoreq.(10/19).times.(197-2.54.times.10.sup.-17 .times.c.c.) (2).eta..gtoreq.c.c./(3.6.times.10.sup.16) (3)A method which can prepare a compound semiconductor crystal doped with an impurity and having a prescribed carrier concentration with excellent reproducibility comprises the steps of melting a raw material for the compound semiconductor crystal in a crucible, and controlledly cooling the obtained raw material melt, thereby growing a crystal. The time required for cooling the raw material melt from the melting point T of the raw material to 2/3T is so controlled as to adjust the carrier concentration to a prescribed level.

Abstract: A neutron radiation detector is described. A semiconductor material is populated with helium three (.sup.3 He) atoms to increase its overall neutron capture efficiency. Upon capture of a neutron by a .sup.3 He atom, a tritium ion and a proton are generated with energies of 0.191 and 0.573 MeV, respectively. These energies are deposited in the semiconductor material creating electron-hole pairs. The electron-hole pairs are withdrawn from the material by the application of an electric field and are collected as charges at the terminals. The associated circuitry processes the charges into pulses with these being counted and their sizes measured. The results are recorded and displayed. The number of pulses are a measure of the number of neutrons absorbed in the detector and of the neutron flux of interest. In many instances the detector can also be used to detect and display non-neutron type radiation or simultaneously neutron and non-neutron forms of radiative activity.

Abstract: When a Si single crystal 8 is pulled up from a melt 6 received in a crucible 2, the state of eddy flows generated in the melt 6 is judged from the temperature distribution of the melt at the surface. According to the result of judgement, the gas, i.e. N.sub.2, Xe or Kr, which causes extraoridnary deviation in the density of a melt 6 is added to an atmospheric gas, so as to keep the eddy flows under unstabilized condition. The effect of said gas is typical in the case of crystal growth from the melt to which a dopant such as Ca, Sb, Al, As or In having the effect to suppress the extraordinary deviation in the density is added. Since the single crystal is pulled up from the melt held in the temperature-controlled condition at the surface, impurity distribution and oxygen distribution are made uniform along the direction of crystal growth. A single crystal obtained in this way has highly-stabilized quality.

Abstract: The object of the present invention affords a method of feeding dopant and a dopant composition used therein for easily preparing single crystals having a desired doping concentration during semiconductor substrate fabrication.In accordance with the present invention, a water solution containing oxides of the dopant is first added to the liquid containing colloidal silica. The colloidal silica can adsorb the oxides of the dopant to form a dopant composition. Around rod-shaped polysilicon, that is polysilicon rod, the dopant composition is discontinuously coated on the periphery of the polysilicon rods spaced at constant intervals and then dried. When the polysilicon rods are melted in an apparatus for manufacturing single crystals by a heater, dopant is protected by the glassed silica without evaporation. Accordingly, the dopant can be provided at a predetermined concentration to sustain the grown single crystals having a doping concentration as required.

Abstract: When a B or P-doped Si single crystal is pulled up from a B or P-doped melt by the Czochralski method, an element such as Ga, Sb or In having the effect to reduce the heat expansion coefficient of said melt at a temperature near the melting point is added to said melt. The additive element stabilizes the temperature condition of crystal growth so as to control the generation of eddy flows just below the interface of crystal growth.When a Ga or Sb-doped Si single crystal is pulled up from a Ga or Sb-doped melt, an element such as B or P having the effect to increase the heat expansion coefficient of said melt at a temperature near the melting point is added. The agitation of the melt just below the interface of crystal growth is accelerated by the addition of B or P, so as to assure the growth of a Si single crystal from the melt having impurity distribution made uniform along the radial direction.

Abstract: A method for producing lutetium oxyorthosilicate crystals includes maintaining the interface between a crystal and the melt from which it is pulled substantially flat as the crystal is grown. In a Czochralski growth method, the rate of rotation of the crystal and its diameter are typically controllable to provide the flat interface as the crystal is pulled. Crystals produced by this method exhibit less variability in scintillation behavior so making them particularly suitable for spectroscopic uses. Such crystals find uses in borehole logging tools.

Abstract: An improved method is proposed for the preparation of a semiconductor silicon single crystal of N-type by the Czochralski process, which is free from the problem of occurrence of delayed OSFs as defects in the single crystal even after prolonged storage at room temperature based on the discovery that presence of a certain amount of aluminum in the melt of silicon contained in a fused silica glass crucible acts to suppress occurrence of delayed OSFs as a type of defects in the single crystal while copper as an impurity acts adversely in this regard. With a known fact that an about 30 .mu.m thick inner surface layer of the crucible is melted down into the silicon melt during the single crystal pulling-up process, namely, the invention proposes use of a crucible of which the inner surface layer of 30 .mu.m thickness contains aluminum in an average concentration of 40 to 500 ppm by weight while the content of copper is as low as possible not to exceed 0.5 ppb by weight.

Abstract: In a process and a device for the controlled feeding of a melting crucible (13) with doped particles (2, 2a) during the drawing of a crystal (16) by the Czochralski method by the control of a flow of particles (2, 2a) from a source (1) to the melting crucible (13), the source (1) is equipped with a conveying device (4) for discharging the particles (2, 2a) at adjustable rates per unit time. A crystal (16), formed from the particles, is withdrawn from the melting crucible (13) at a predetermined rate per unit time. So that the control process can be conducted smoothly over prolonged periods of time with precise doping, the particles (2, 2a) are separated into individuals on their way to the melting crucible (13) and counted by at least one sensor (21, 22). The sequence of count pulses is sent to a counter (25) and compared there with a corresponding sequence of reference input pulses.

Abstract: A method and apparatus for pulling single crystals from a melt of semicontor material, in which a monocrystalline seed crystal grows to form a single crystal, the seed crystal being dipped into the melt and raised in a controlled manner in the vertical direction with respect to the melt, while the melt forms a molten pool which is held on a support body only by the surface tension and by electromagnetic forces due to an induction coil. This method includes recharging the melt with semiconductor material in solid or liquid form during the growth of the single crystal.

Abstract: A method for growing an antimony-doped silicon single crystal having an oxygen concentration of 12 ppma or more is employed wherein the pressure of an atmospheric inert gas within the furnace is set at a range between 10 and 50 millibars (1000-5000 Pa), and also the reference rate of rotation of the quartz crucible is set at 5 rpm or more while pulling an antimony-doped silicon single crystal having an antimony concentration of 6.times.10.sup.18 atom/cc or more from an antimony-doped silicon melt contained in a quartz crucible according to the Czochralski process. The reference rate of rotation can be increased in accordance with the increasing length of the pulled single crystal, and further a pulse-like change in rotation rate can be superimposed over the reference rate of rotation, so that the pulled single crystal can have a high and axially and radially uniform oxygen concentration throughout the entire length of the single crystal.

Abstract: In an improved Czochralski process for growing silicon crystals, wherein a single-crystal silicon seed is pulled from a molten silicon source to grow the crystal therefrom, a pre-oxidized arsenic dopant is added to the molten silicon source to alter an electrical property of the grown crystal. The pre-oxidized arsenic dopant includes granular particles of metallic arsenic having a surface film of arsenic oxide, the surface film having a thickness of ten microns to one millimeter. After doping, the molten silicon source is moved from the grown crystal, and an applied temperature is increased to burn excess pre-oxidized dopant.

Abstract: A dopant (76), such as antimony, is cast around a seed crystal (10) to form a seed-dopant assembly (14) that facilitates doping of a molten semiconductor (36), such as silicon, in a crystal-growing furnace (34). To grow a doped ingot, the seed-dopant assembly is held in a relatively cool part of the furnace while the semiconductor is melted. When the semiconductor melt is ready for doping, the seed-dopant assembly is lowered to a position just above the melt. Heat transferred to the seed dopant assembly from the melt causes the dopant to drop off the seed into the molten semiconductor without splashing and without immersing the seed.

Abstract: A single crystal material is filled in a crucible, and the whole of the single crystal material is melted to contain doping impurities. A solid layer coagulated upward from the bottom of the crucible is rendered to coexist with a melted layer over the solid layer. The solid layer is melted from the upper side thereof while pulling the single crystal from the melted layer. The ratio by weight between the solid layer and the single crystal material at the start of pulling is adjusted, together with the ratio by weight between the grown single crystal and the melting solid layer. The single crystal is thus grown while changing the volume of the melted layer.

Abstract: An apparatus for use in solidification of a doped electrically conducting material and for use in monitoring said solidification is provided. The apparatus includes a first forming means for forming a liquid of undoped material in thermodynamic equilibrium with a solid of the undoped material, and a second forming means for forming a liquid of doped material in thermodynamic equilibrium with a solid of the doped material. Solidification of the conducting material occurs at a solidification interface between the doped liquid and the doped solid in the second forming means. In one preferred embodiment, the apparatus comprises a conductive bridge for short-circuiting the liquids.